That's about the smallest height you could get away with, if that's as tall as you can make it then you probably shouldn't bother with a veg period, just flower from seed or clone and they will fill the space, assuming they get plenty of light.
Ideally you'll want 7-10,000 lumens per sq ft of growing area. You have 5.6 sq ft, so you want between 39,000 and 56,000 lumens for optimal lighting.
The volume of your space is only 13.4 cubic feet, so unless you have a really restrictive filter or lots of ducting/lots of bends in ducting, then a bathroom fan should suffice to keep air flowing.
You seem to have an idea of the basics, keep reading, keep asking questions, we'll do our best to help.