It would be absolutely wonderful if that's the fix. What you may want to do is grab the older dll from before the last dll I committed. Use that in tangent with Salvelinus's last save and stress test potential solutions with the sun bear unit. If you can find a way to lock onto something wrong in the animation then that's going to give us the keys to a true fix. It's entirely possible you are right about the bActAsRanged tag use...
bActAsRanged =0 didn't work.

A cave lion attacked my Atlatl and then CTD; tried turning on quick combat and the game didn't CTD when it attacked.
The interesting thing is I also tried moving to the plot I knew the cave lion was in, this triggered a stealth defense so the cave lion was visible after the battle, my Atlatl unit survived by a lucky withdrawal. When I then hit end turn without quick combat the cave lion attacked and I got to see the whole combat animation without issues (probably because the cave lion models were visible when it attacked).
If I turn off quick combat (offense) and then move into the plot I know the cave lion is in, the game CTD during my turn, when I attack the invisible cave lion by triggering its stealth defense.
I firmly believe this crash is caused by the opponent being invisible either when the player attack it or when the opponent attack the player. Are you sure unit models are turned visible in battle before animations kick in? How are they made invisible in the first place?
Edit: I even tried removing all animations from the cave lion, but the game still CTD'ed when it attacked showing that even static un-animated units crash the game when they attack when invisible, mind, only when they attack the human player. Fights between the computer controlled teams are always quick combats.
My testing here has shown without doubt that no manner of XML or unit art/animation modding can fix this particular CTD. The only solution, if it exists, would be in the DLL.
It also shows that the problem is most likely not isolated to only NPC teams, that if an invisible babylonian unit would attack my not babylonian unit the game would CTD without having quick combat (defense) ON.
A small annoyance with Hide and Seek is that no invisible units are visible in the WorldBuilder making it very complicated trying to ascertain the number of animals on the map and how spawn modifiers should be adjusted. One has to just click on every empty plot with the unit edit to see if the unit edit window pops up. Could you make it so that invisible units are visible in the worldbuilder?