The necessary Barret animations are also included in the Avalanche installer.
I tested this and there is still a small issue in the animation. He will jump towards the mob as if he's performing a Mug, but then fires his gun like normal instead of doing the melee attack. What I did to test this:
1. Clean install of the game.
2. Installed the Asmodean Barret under Battle options from the latest UMI.exe.
3. Extracted the 4 corresponding files (sbda, scda, sdda, seda) from battle.lpg.
4. Another clean install of the game, followed by a Timu+Kleyon+Asmodean install through Bootleg.
5. Copied and replaced the 4 files in battle.lpg.
I could have done step 2 wrong. When you mentioned Avalanche installer, I tried the Avalanche Hi Res installer but didn't find the files. I believe you when you say it's fixed for 0039, so this is not to knock your efforts. I am just posting to learn as I'm slowly piecing together things. It's exciting to learn how the game works