Yes I greatly appreciate you putting more time into this one!
Unfortunately, the output isn't quite usable yet... no 3d models or textures. There are a lot of additional .AST files that get spewed out from the big ones. Trying to extract those results in more .AST files. If you keep extracting them, you essentially see a pattern where the results are the same as all of the .AST files in the top level directory. So a tiny .AST file could extract into many many .AST files that are much larger than the tiny one that you started from which includes a copy of itself. (That sounds a little wordy to me, hopefully it makes sense!)
Some thoughts on some of the resultant file types:
Any idea what the .XPR files are? I tried your Quake 4 XPR bms script, but it didn't work (couldn't read 1 byte).
You mention in the func_getTYPE.bms that you are unsure of the usage of .GD files. Looking at them in a hex editor, they look like animation scripts of some sort. They contain some variable declarations and then mention animation parameters. I'm sure that you've already looked at that though, but just in the odd case that you haven't... maybe that could help diagnose their usage?
I heart you AlphaTwentyThree!