I did some .ini editing for anyone who doesn't want to do it themselves. Short version, this file will, out of the box, make all the stuff from A Better Advent available and at the proper force levels, as well as making it more "balanced" by excluding bosses, and more "fun" by excluding enemies with few/no interesting features.

You can find it here (copy text from file and paste into the mod's Unknown.ini): https://pastebin.com/jLVagKY6

Full changes:

1. Updated for A Better Advent; most if not all ABA units are now in the file, with boring stuff and too powerful stuff (like bosses) commented out by default (just delete the ; at the start of the line to add them back).

2. Changed all units to use the same force levels they would for ADVENT in ABA; in other words, aliens are only available to join your squad if they would be available to spawn as enemies.

3. Commented out extra abilities except Ever Vigilant.

4. Set # spawned to 1 and chance to 100% (they still don't always show up though).

More detailed instructions: If you are using the community mod manager (which you should be), find Unknown Ally in it and right click, select "view in explorer" to get to the mod folder. Then go to the mod's Config folder and open the Unknown.ini file, paste the text from the link above into the file overwriting all the text already in there, then save.