Hi all, im about to do a setup for someone and it's been a while since i used ubiquiti and was wondering if you could help answer some questions

for the primary setup traditionally you would use a USG and a cloud key, I see those have been replaced with Cloudkey and you can use either Gateway Lite/Max

but I do see this alternative the Unifi Express and the cloud Gateway Ultra which has both built into each other. only down side it seems unifi express can only have 4 devices?

so my first question is if i were to go the Unifi Express route is it confirmed I could expand the unifi network with a cloud key. And would a Flex mini take up 1 of those device allocations? Ive never used one so not sure if it's managable.

2nd question how is your experience with the U6 and why is it the same price as the u6 Lite, i know the specs are some what similar. and can they handle a cieling thats around 15ft high