1st use clones i say that because growing from seed the plant should be at least 2 ft high befor you att flowering. you dont have this problem w clones as they are the same age as the plant you take em from.

your closet has 8ft of headroom this is your only advantage. build a stage one foot off the ground place your tanks inder the platform. good for storage too

build a 2nd "shelf" to fill the entire 2x4" area then tape it on all edges against the wall (use duct tape) - this bottom shelf will be your flowering shelf make sure no light gets into the bottom chamber hang some panda over the door from the 2nd shelf made sure no light seeps thru

from the 2nd shelf hang one T5 flo sunwave with 5 orange tubes and 3 blue tubes on a pully system so you can raise and lower your T5 to the right height - do the same with the ceiling except on the veg shelf ya wanna use 5 blues T5s and 3 orange ones

be careful with your air circulation when you close the door you might want to install some of those small axial fans and leave the door open as much as you can

you cant use HIDs in there as the heat buildup will kill your plants in just a few hours