Some unassorted thoughts: I use my operator/drifter only as utility. Self revives, crossing great distances, reviving teammates. When I used Zenurik I'd also switch to use the energy regen ability, but these days I use Madurai in order to be able to self revive on higher levels. Also Void Angels.

I have built some amps, mainly for levelling. 777 got recommended to me at some point and it works well enough so I've stuck to it.
I use the tether and heal teammates on invis arcanes on my operator. As well as two damage ones on my amp. Most of them aren't maxed.

I have maxed out Naramon, Zenurik, and Madurai and have all waybounds.
Way back when operators were first introduced I liked Naramon because I used a lot of melee. Then switched to Zenurik for the energy regen. Only (relatively) recently switched to Madurai, though I might have done so earlier had I been actively playing these last few years.

I want to like operator mode. I like the idea of switching out of your Warframe and just running around as a (mostly) regular dude. But none of the amps I've used feel great to shoot, the movement animations all feel awkward, and the operator is just fairly weak. I avoid Duviri whenever I can for the same reason. It just feels clunky and awkward and not good.

Also I use the drifter. Part of the reason being the operator voice lines which have become grating over the years. "tHe GriNeEr DeTeRiOrAtE oVeR TiMe, iS tHaT wHaT mAkEs ThEm AnGrY?!?!?"

1. Not really no. Being a fragile human isn't great. I do prefer Drifter because I like being able to forward roll though.
2. Enough to get a 747. Farmed another amp that I still have before I had the rep for 747 but I don't remember what it is. I cannot be arsed to farm another. Quill/Vox rep is pain.
3. Do have arcanes. Magus Vigor (5), Emergence Savior (3), Eternal Eradicate (5), Enternal Onslaught (2). Are they the best? Dunno, don't care. They're what I have.
4. Madurai for the that sweet, sweet DPS boost. Maxed out, bought multiples of the million point cosmetics and shit.
5. Got most of the schools maxed out. Got cosmetics from like 4 of them even.
6. I put lenses on stuff and don't sweat farming focus. Get what I get when I get it.

Operator/Drifter functions well enough. But I wish it had some QoL tweaks like moving a little faster, being a little tougher, just removing Transference Static. I only die in Op in game modes that require me to use it a lot coughOrphixcough and it's not my fault Op is fragile as fuck. Stop punishing me for it in game modes that require it's heavy use.

I do like to use Op to clear mag anomalies and it's got some utility for hosing down Archon hunt adds. I also enjoy Drifter mode in Duviri but I fucking hate Sirocco. I really hate that it doesn't pull damage from my current amp load out. I'm fine with it continuing to use the pistol mechanics but for the love of god let me use my actual Amps stats. Especially on Steel Path. The Sirocco is so bad with no decrees. Maybe getting to use Nataruk like TNW?

Operator/Drifter could use some gear access tweaks I think. Both in Duviri and regular starchart. Maybe mods for Amps? A few more quest reward amps? The default amp is trash and trying to rep grind with it is absolute ass. Sirocco is a nice little boost from it but we could use another upgrade or two to fill the gaps as who wants waste rep buying mid amps if you just hold out a little longer to get a really good one?

• I love School synergies. So I don't use my Drifter as a "warrior" per se, but I do actively use School abilities. I typically run Vazarin, and the Void Snare mass-finishers are great for proccing Trickery and stacking Crescendo. Void Snare with the Phahd scaffold is exceedingly powerful. Drifter mode offers good mobility if I'm on Ivara.
• I have an Arcane Adapter-fitted 777 and 547. I plan to go through and make XX7s to get a feel for the other Scaffolds, but Phahd seems to generally be the best for Last Gasp recoveries.
• I use Magus Lockdown and Magus Melt for general use (Lockdown covers CC and demolysts; Melt covers Void Angels and Thrax). My 547 is fitted with... something. Whatever the standard became when the Zariman amp arcanes dropped.
• I almost always use Vaz. I started with Naramon. Vaz is, imo, the best general purpose school as it gives you free emergency invulnerability and lets you easily stack Crescendo. I use Madurai on Gyre and my health tank Sevagoth so I can lock in +125% power strength on their abilities. All my schools are maxed, and I have fully finished collecting all the Represent swag.
• I did most of my focus farm before Zariman, so my main methods of focus farming were fitting different nuke frames with Eidolon Lenses and farming ESO. When I managed to catch tricap groups with the alliance, I would use shards. I mostly did not enjoy the Sanctuary farm, as it was very repetitive and one-dimensional, but some methods were fun (like Nezha with the Akarius). Nowadays I could quite happily do it on Gyre or Sevagoth as they have very mobile nuking styles.
• Phahd spam is powerful, but it pales in comparison to the kinds of chaining beam incarnons we have now, like Torid and Boar. Void Snare spam is theoretically very powerful for objective defense, but I play Warframe for the movement, so it's not very fun.
• Everything about Vazarin is incredible.
• It's effective, but "maining" Drifter/Operator seems to run contrary to what makes Warframe compelling and unique. Drifter/Operator feels best to me as a component of your loadout.

1: Yes! It took me good time to get my booger goblin and pedro pascal to look good, so I use them regularly.

1a: Drifter. I don't really care for playing as a kid.

2: I've got a gilded 747 and a bunch of mastery fodder. I really need to get an angel popper built one of these days...

3: Unairu. I like having armor strip available on every frame and weapon setup. Maxed it out, still haven't gotten all the represents.

4: I've unbound Vazarin and Madurai, working on Zenurik then Naramon.

5: just farting around got me a long way, duviri and zariman really helped. I've actually unlocked Saryn Prime just recently and have been running a few solo SP survival missions to grind for orokin cells, tellerium, and plastids when I can stomach it.

6: 747 w/ armor strip and unairu wisp go BRRRR. Comparable to a warframe, but less flexible.

7: Armor and Shield Strip is less useful to me now than it used to be, but I've got the heavy blade crit arcane and like to thwack things with it. I also have the energy mote arcane for fueling warframe energy in bursts of 10-50.

8: Gimme a bigger amp. I want a big 2h weapon. I actually don't care for the duviri weapons, but I wouldn't say no to having them around. And non-sirroco appearance for the drifter's amp, pls.

To answer my own... well at this point survey:

• Yes, I do. Quite a bit actually.

  • I greatly prefer the Drifter.

• A decent amount, I'd say. A bit of research and a bit of grinding.

  • Yes, I have several and know of a few more I could build and might like.

• Yes, both types and I find them somewhat necessary.

  • Magus Replenish & Emergence Renewed on Drifter, Eternal Eradicate & Virtuos Strike on Amp.
  • Yes, all of them.

• I main Madurai

  • Yes, it is.
  • I've unlocked everything in the school and two 'represent' cosmetics.

• Yes, all of them.

  • Yes, I've unbound everything.

• Farming Thrax and Void Angels on Cascade

  • No. It's a high-intensity grind that I've never encountered someone else willing to do. In short: it's pure pain.

• Notably less effective but still useful.

  • Sometimes significantly more effective and always useful.

• Yes, Void Sling. I can't keep up with most other Tenno's bullet jumping but VS gives me an effective alternative to not be left behind.

• I like it, I find that it has great utility that supplements every Warframe pretty well.

• Yes, whenever I feel like it I do change to my operator unironically and sometimes for the utility they bring
  • Operator, I wish I could say I love them both equally but for cinematic purposes I still go into Operator, I do swap in between often for regular gameplay however
• Not much, I just got them all and maxed them like any other Mastery Grind, the only effort that went into them was using a different combination each time, no repeated parts across the board
  • Yes, not a single part repeated across all my 8 AMPs (mote included)
• Yes, obviously they make a great change when compared to none
  • Operator: Emergence Saviour and Magus Repair, AMP: Eternal Onsalught and Virtuos Strike
  • Yup, all Arcanes from Operator and AMP maxed
• Unairu
  • Yes, Im into being a tank or protector
  • "Prestige" Obtained everything and have a lot of million points lying around
• Barely
  • Yes, everything that can be
  • I did all my Focus Grind before there were more than 1 Method, so just obtaining Affinity on ESO
  • It's okay, one daily run of 20 minutes, ESO could be better however
• Equally effective, I can kill with my Operator as much as my Warframe (Chroma) really, unless the Enemy cant be armor stripped
  • I would say in general lines is okay, any Warframe can complete any kind of Mission, same with operator
• Invencibility, both for me and my Warframe so I tend to play around it for Defense or Control
• Bring Void Dash back