It's possible. I soloed IWD/HoW/TotLM with a fighter/mage. The final battle was not that bad. I also did it with a 2 member team before that, and it was
very easy (well, all things considered, of course). What I found out about that game is that melee is more important there than magic (which is why I liked it so much).
As far as IWD2 goes... who cares, it blows
-A