1. Well, if this is your first time playing Icewind dale II, then I definatley wouldn't reccomend soloing. In my opinion soloing through IWD II is way too hard since there are so many enemies, but mainly becouse, enemies decrease in XP the higher level you go, so you will be a highter level than average and end up going through levels without getting XP. (In case you didnt know, IWD II is set in 3rd ED rules instead of 2nd ED like all the other bioware games)
2. 2-3 characters, or probaly 2 since three is uneven, ends up running into the same problem as a solo character. You will be going to be tromping through dungeons, killing everone for no XP.
3. A 4 person party is a solid party, though I wouldnt take it over a 6 person party cuz of micromanaging. A good solid 4 person party is
Dwarf Fighter4/BarbarainX
Human Fighter4/ClericX
Aasimir Sorcerer
Drow ranger1//paladin2/rouge1/mageX (thanks to marty for that build)
4. First off lemme say, DONT TAKE THE PRE MADE PARTY'S!!!! THEY ARE HORRIBLE. With that said, a six-person party is probaly the overall best choice for a non-powergamer. You won't run into much XP problems (unless you go into HOF mode and you might have to level squat a few times)
A solid six-person party is
Dwarf Barbarian
Aasimir Paladin
Tiefiling Theif
Human Cleric
Aasimir sorcerer
Drow Wizard
Although this is just my opinion, really a lot of the fun comes from making your own party, so these are just suggestions.
If you are a powergamer, I'd go with a 4 person party, if you aren't, I'd go with a six person party. Well, I hope all this typing had provided some help in your quest to pick an X number party
