@Serp:
Concerning Communitas: it's designed to augment/adjust the base game without adding onto it too crazily. The AIs are substantially smarter for both barbarians and AI Civs, and the barbarians mostly got special movement abilities (woodsman, mountaineer, etc) which let them move faster in specific terrain types, based on where their camp spawns. They give a not-inconsequential amount of gold for capping their bases too. The huge difference between the base game and Communitas though is gold. In Communitas, you get a real economy; not a delicate maintenance dance, so you will be buying a lot of stuff. Rome likely got a lucky start location in your game, and rushed military (a solid player strategy that is often used). I kindof find those things neat, like Rome behaving like Rome

but to each his own. Communitas is ultimately for those who want 'oldschool civ' style back from the previous titles, rather than adding to Civ 5's new style.
Thanks for the advice again! Turned out to be a combo of two things; there was a typo in one of the Communitas files, and some things for other mods that weren't having their dependencies proplerly checked. I fixed those, and then found an InGame.lua in the Communitas folder, which per-instructions I deleted (replacing the one generated by MPMPM just made things worse).
The game runs a lot better now; scripts mostly work, tooltips function correctly, etc. I'm stuck with two caviats however. First, while the revised start biases work in single player perfectly, they appear to be non-functional in multiplayer. Additionally, the start location reveal still doesnt work specifically in multiplayer, though that's less important.
The other bug is some kind of corruption of the cache if one ever tries to re-start/join a game after starting one, unless I exit the game entirely. I've repeated this multiple times and circumstances. It only occurs when you exit to main menu, then start another game (mp or sp). Once corrupted, it will remain so until you wipe the cache or reload without the modpack, then reload again with it (forcing a core game/dlc cache refresh). It's easy to work around, but odd, none the less.
If anyone happens to have any ideas about the remaining bugs, let me know! I'll probably be poking around in the Communitas source trying to figure out what's breaking the start conditions in mp. I'll post the modpack I have so far soon as I've played through a game with friends to ensure both stability and reload/rejoin functionality