I downloaded and installed BUG v4.1 - successfully as far as I can tell.
BAT 2.0 includes BUG 4.0. It can be difficult for end-users to stay current on all the latest features when mods like BAT package other mods (BUG, BULL, VD, parts of BlueMarble) that are also progressing. While you
can upgrade BAT to BUG 4.1 by copying over the files from BUG's Assets folder over BAT's Assets folder, sometimes problems may arise. I think 4.1 should be okay, though.
I strive to keep BUG backward compatible. You can always use the older saved games with a new version of BUG, and you can always use your old settings files as well.
1. Do I now have all of the latest and greatest available features of BUG, BAT and BULL. If not, what do I need to do to get them?
If you copied the new BUG files over BAT, yes.
2. Same question re: Blue Marble.
BAT includes only
some if BlueMarble, and BM hasn't been upgraded since BAT's 2.0 release.
3. If I download and install BBAI will I loose any of the features of the BUG/BAT/BULL MODs?
You can copy the BBAI CvGameCoreDLL.dll file into BAT's Assets folder, but you'll lose BULL (extra hover text information). BBAI includes the UP, and jdog and I are hoping to be able to release a BULL/BBAI merge. C++ merges are more difficult, especially since both include the UP.
4. Same question re: PIG.
PIG includes both a DLL and BUG and some XML, so it will be harder to merge with BAT. You would definitely need some logic and computer skills to merge them yourself. You might be better off merging VD with PIG and installing BM separately.
5. How about LoR or RoM and others?
These are like PIG in that they are more complex mods that alter gameplay, graphics, and the interface. I believe both include BUG (4.0?), but upgrading them to BUG 4.1 would require some Python (programming) knowledge. I think they upgrade BUG as new versions are released pretty quickly, though.