if i have lets say a desk plan , could i show someone in lumber my measurements for the wood pieces and have those cut ? i live in an apartment so i cant really cut wood at home, and i need lots of it for prop weapon making

As long as you have measurements. Ask for help as soon as you arrive, sometimes there is quite a wait.

They don't do angle cuts tho.

Yes, as long as you have the measurements they can make the cuts. Depending on how many cuts there are, they may charge you $0.25 a cut after so many.

Yes, I have had lowes cut wood for me when we lived in an apartment too at no cost. Only thing I am unsure of is how much they are willing to cut for free