The special features are hard to replicate. Hue sync won't work for example. That's why I still use the hue hub in addition to a zigbee stick for non-hue lights and switches. But if they want a login I'd rather drop hue sync and just add the lamps to my zigbee stick.

Not all Philips bulbs actually, only Hue. They have another line called Wiz which uses wifi.

I looked this up a while back. Someone wrote code to try to replicate it in homeassistant on their forums. If I recall correctly, it didn’t work quite as well as the hue version but I haven’t have a chance/reason to try it yet. Maybe someday soon.