Unless you already own all of these parts, acquire an “-8e” HBA for your “System 2” and install an expander in “System 1”. Many expander cards only draw power from the PCIe slot connector and are suitable for use in a JBOD chassis.
There are a loooot of connections in here so many points for failure, and a lot of money spent on cables
I hope you have very low humidity, going that low can create a risk for mold forming in your walls.