I use BI w/ both and haven't had any problems. The resource-only version worked okay too, but apparently the AI makes suboptimal purchasing decisions in that case.
Note that you *can* set AI difficult/attitude when using a modded AI, if by "modded" you mean "modified using map or mod commands." What you can't do is generate the pretender *using the in-game GUI* and start the game as a human, then set to AI. What you can do is generate the pretender as part of a custom map scenario (modify the map you're going to play) and set it to AI from the very beginning. Note that you can make the AI pretender pretty much arbitrarily powerful in that case, too, and/or give him some starting items or SC companions. For instance, you could let each AI nation start out with 1 Ophan commander.
(Ashdod national summons.)
Oh, yeah, I suspect setting research to Easy might be a good idea. The AI doesn't really seem to target its research very well, unlike a human, so if you set it to Easy research there's a slightly higher chance of the AI having the right spells it needs for a given situation. (Whereas a human will just compensate for harder research by beelining for the most important spells.)
-Max