Enough closet space?

This is an illustration of the closet measurements.

As you can see in the crappy photos, the roof slants down at an angle.

My questions are:
1)With the closet cleaned and empty...is there enough room to harvest a few plants at a time *veg*+*flowering*?
2)How can I control the temperature/humidity, without adding any holes in the walls?
3)Do I just need to go ahead and make a grow cabinet to fit the size of the room? (If I need to install aircontrol and stuff into the walls....I will have to make a cabinet because I cant make holes in these walls for personal reasons.)

P.S.
LOL @ the MSPaint design of my closet :)

Top44 is the plant of choice to be in the closet. I wanted to setup with a 400w HPS light, but my friend says it will get to hot, hence me looking for suggestions here. Thanks!

Please delete this thread, it was moved to the correct section Closet/Cabinet Growing