Kk, give this a shot and then a couple notes:
I'd use KSE 3.3.3, as all the others kept crashing for me
Whenever you want to use KSE, you're going to have to manually move your saved games to the GameData folder, run KSE and make your changes, then move the saved games back. Pain in the ass, yes. (Also backup saves before doing any of this.)
So take the saves folder: Users/YOURNAME/Library/Containers/com.aspyr.kotor2.appstore/Data/Library/Application Support/Star Wars Knights of the Old Republic II/
And move it to HARDRIVENAME/Applications/KOTOR2.app/Contents/GameData/
Make your changes in KSE and now move them back.
Add a new engine, I use WS9Wine1.7.36.
Create a new wrapper with this engine, name it whatever, i.e. KSE.
It might ask a few things, i.e. gecko, mono? and maybe network. You just need the network one.
Once done, View wrapper in Finder, right click, Show Package Contents and open Wineskin.
Click Advanced, then the Tools tab.
Under Utilities, select Winetricks.
Under dlls, select dotnet20 and Run.
Take a nap.
Close that window and select Registry Editor (regedit) under Wine Tools.
Under HKEY_LOCAL_MACHINE, right click on Software and select New, then Key.
Name this new folder LucasArts and create a new key in that folder named KOTOR2.
Now right click on KOTOR2 and select New, then String Value and name it Path.
Outside of this, you need to find the KOTOR2.app game data , and since you in installed via MacStore, it should be something like HARDRIVENAME/Applications/KOTOR2.app/Contents/GameData.
Copy that whole path, from the harddrive name to data.
Back in Registry Editor, modify Path and paste the above path in there.
Change all of the back slashes to forward slashes and add Z:\ before your pasted content. e.g. Z:\HARDRIVENAME\Applications\KOTOR2.app\Contents\GameData.
Click OK and close Registry Editor.
Under the Configuration tab, select Install Software, then Choose Setup Executable.
Find wherever you downloaded KSE and Choose.
Get your KSE on and don't forget to move the saves back to their original location.
Now another pain in the ass thing, you will have to "install" KSE every time you want to use it. You won't have to do all the above, just open the Wineskin wrapper you made and Install Software, Choose Setup Executable, etc.
Work through all of those shenanigans and let me know how it goes or if you have any questions. Feel free to holler at me on Discord too. Once we get this going, we'll tackle Party Swap.