As Vlad has mentioned before:
QUOTE(Vlad @ Sep 5 2006, 04:57 PM)
If you like Tactics or Improved Battles or any other similiar game enhancing mod, I would recommend installing Improved Anvil with NeJ2. It is most probably compatible with NeJ2, but it should be tested in practice for 100% certainty. The party after finishing BG1 + NeJ2 Part 1 is too powerful and it is a good idea to have IA's enhanced battles added to the game, specially because IA is so far the only tactical mod which is most likely compatible with NeJ2.
In other words, after finishing the first part of NEJ2, your party will probably be powerful enough to handle IA's battles much more easily. So, I don't think that you should worry much about the difficulty.
Moreover, consider the fact that IA is not comparable with any of those other mods you mentioned. IA is not merely a tactical mod; it adds lots of new quests, a unique item randomizer, and a big amount of new content to your game.
Of course, the full compatibility of IA and NEJ2 has not been tested yet. But as mentioned before, if you encounter any conflicts between the two mods, we will be here to resolve any possible issue.
The final decision is yours to make, of course.