Your buddy’s shop might have an AC machine so you can properly evac the system. Or you could just bust it open, I guess. You really don’t need a lift for this.
The cleanest way to do it is get an AC delete heater box. That is what I did in my 82. But I think they are hard to come by. If you are nutty about it, you could find an AC delete heater control setup to for the dash, but you don’t need it. I think I saw a tech article on it at thirdgen.org. I’m not sure how you make it look good w/o that box. You can just tie the unused wiring out of the way (or cut it out, I suppose).
The belt is the only other item of real consequence I can think of. Does the AC in your car have its own belt or is it a serp setup (I don’t know the year by year details)? If serp, there is an AC delete pulley you can get. Check thirdgen.org for a GM part number, and buy it on gmpartsdirect.com.
It does clean the compartment up nicely, and changing plug is easier. But I wish I never pulled the AC out of my Trans Am. It would have helped resale value. Yes, I know, you don’t care. I didn’t either. Until I went to sell it. And mine didn’t work. Sounds like your does, bonus.
I might be misunderstanding you, but I wouldn’t take the heat out too. Unless you are building a race car. I guess if you are, you just weld some patch panels in, smooth it out & paint it.