Looks like you have a good idea for the trellis. I'd say like 8-12 inches, depending on strains, and your planned finishing height.
I've never done Cheese, personally, but you might have to keep your inline and carbon running 24/7 towards the end. There's usually no problem keeping temps up, unless it's really cold where you live. Mine smell so badly that, (as ridiculous as it sounds), I actually pay for 3000W of heating, just to keep room temps high, and still be able to pull air out through my carbon filter. (Yes, during lights on!). Unfortunately, I found out about my own stink when I mowed my lawn. I was like fuck, I gotta fix that now!
Just remember, it's said that you need to keep your humidity low, for the carbon to activate in your filter. I think it's recommended at like 50%, or otherwise you could just be blowing out beautiful scents into your neighborhood...
If you are asking if you 4 inch filter/fan combo is enough, you kinda gotta figure that one out. Every fan has a "cfm" rating. Just figure out how many cubic feet you're trying to ventilate, and check and see if your fan and filter are enough. I personally overkill on my fans. I figure the move air that is moved faster, the less stink, and the less noise that will be made from fans running.