The good thing is you have a lot of square footage. The better thing is you don't need much room for deer processing.
Two questions first: What kind of floor does your building have (concrete, carpeted plywood etc.)? And do you have or could you install running water in the building?
With that building, I wouldn't bother with a skinning pole outside. Move it all inside where you're out of the elements.
A simple hoist in the middle of the processing area would be perfect. Electric or chain, it doesn't matter. I think I paid $40 for my 1/4 ton chain hoist, and it works great. Pick up a $20 gambrel too.
As far as knives: I use a guthook knife for skinning and a pair of fillet knives for deboning. For final cuts, I use a long, straight edge carving knife. I also use a bone saw for cutting up the carcass after deboning. I think they’re around $15 or so.
Personally, I don't use a vacuum sealer. One wrap of sling wrap (or plastic food bags) and butcher paper is inexpensive and very effective. I have wild game in my freezer from 2004 that's as good as the day it went in there. Cabela's sells large rolls or butcher paper and dispensers at a reasonable price—much cheaper than the small rolls the grocery stores sell.
I'd suggest adding a counter section out of that plastic material they use for cutting boards. You may be able to get section at a local home center pretty cheap. I apologize, but I don't remember what the material is called.
A decent grinder is a must, in my opinion. You don’t have to go top end for quality though, but I’d stay away from the $50 ones with the plastic cases. I had one of those, and I don’t think it made it through one deer before it broke.
If you can install or have running water, you may want to put in a small washtub for cleaning up afterwards. Good lighting helps too. Maybe think about a couple sets of fluorescent ceiling lights.
Aside from that: some comfortable chairs, a stereo and a small refrigerator for keeping beverages cold wouldn’t be a bad idea either.
It looks like you’ve got a great foundation so far. I’d be interested in seeing the finished product. Good luck.