Thanks for checking the .SPL in the game files. I would love to do a full EET install, but I don't have SoD, which is a requirement.
Edit: Thanks to CamDawg in the Beamdog forums, I found the link to the HLA Mod for BG1:EE. You may also want the accompanying Level 40 Rules Tables too, if you don't have any other mods (like DR or RR) which add those class progression tables.
Edit 2: Ok I just tested installing the HLA Mod on Patch 2.5, and I noticed two things:
1) You don't need a modified UI.MENU for the HLA selection screen in BG:EE. The game will still allow you to use the +/- buttons on blank abilities, so your game won't get stuck.
2) The HLA mod fills in those missing .SPL files for the HLAs so their icons and descriptions will appear in the HLA selection screen. All the abilities seem to be working fine, except the HLA traps ("Set Spike Trap", "Set Exploding Trap", and "Set Time Trap") which seem to do nothing after they are set.
Will continue testing and see if I can get the HLA traps to work. Thanks again everyone!