[Axterix]

1. When I first got IWD, I went with my standard good party.
Paladin - She's the leader. And paladins rock in the game.
Ranger - Rangers are cool... but in IWD, was a bit underwhelmed by him. That is, until I went to HoF mode and I needed his summoning spells.
Cleric - good aligned, like the rest of the party. Good aligned clerics rock.
Fighter - Snurg, your typical dumb as a post strong fighter stereotype. Grandmastered in Axes and that served him well with the nice variety of axes in the game.
Fighter/thief - a halfling, this combo also worked well, with the helm of the trusted defender and multiclass/dual fighter only set of gloves that granted 18/51 strength.
Conjuror - A nice powerful caster, with one major drawback, no summoning spells (with HoW installed). A non-problem in the standard game, a bit more of one in HoF mode, but thankfully the ranger was there to make up for the lack of summoning. Also, both level 9 spells in the game are summoning ones, which sucks big time.

My current mostly evil party started at level 1 in HoF mode is as follows:
bard - wanted to try them with HoW's improvements.
Druid - wanted to try 'em.
fighter - pure fighter, pure power
fighter - same as above
dwarven fighter/thief - an awesome combo, very powerful, even with being 10 levels behind the fighters (they are 30/30, she's in her low 20's in both) she's the most powerful member of the party. The token good aligned character in the party.
cleric/mage - Mage side rocks, cleric side blows, aside from cures, dispels, buffs, and the like. In HoF mode, with critter resists, evil cleric damage spells don't do much and I'd rather use the significantly better mage side spells. Plus no ress, no raise dead, no heal (though the druid can cast it).

2. Nothing different with my first party. They rocked, so why change 'em? The current party, I'd have started the druid out as a fighter for at least a level or 2. The ability to use more shields combined with druid shapeshifting would make a huge different in Trials of the Luremaster. Second, I would make the cleric/mage neutral, that way I'd at least have raise dead.

3. Bards and druids do suck in IWD. Heart of Winter though changes that. It adds 4 new songs, including one your bard will sing 99% of the time you play. War Chant of Sith. 10% resist to blunt, sharp, pierce. +2 hp per round. And +2 bonus to AC. Same story for druids. HoW added new shapeshifts, new spells, and higher levels. Those things made druids rock. Now, together, they are a bit overpowered in quite a few places, at least once the druid has Stalkers (aka shambling mounds) which are 50% resistant to pierce and slash, 90% resistant to blunt and 100% to fire. They last 8 hours, in game. Bard songs effect summoned critters... so that means 100% blunt, 60% pierce and slash, and the healing to keep them alive to allow you to use their long duration to the max.

4. With the fast rate of xp in IWD, especially if you have HoW, dual classing is typically a more attractive alternative. After level 9, single class characters outdistance multi-class ones pretty quickly. However, much of what you want is up to you. The advantage to multiclass is your characters have more abilities... and while a party of fighter/mages may be lower level, they pack a lot of spell powered offense. However, do keep in mind the relative rarity of mage scrolls in IWD.

5. Well, if it were me making a party of 6 under those conditions, assuming HoW... hmmm...
Human: Fighter dualed to druid. Specialized in scimitars (large swords?). If you dual at level 7, you'll have +1/2 attack. If you dual at 9, you'll have grandmastery and 10d per level. The access to almost all shields plus druid shapeshift resists and and bard in the party...

Half elf: female bard. War Chant of Sith. Never need to mem identify. Being female, bard, and with a nice int/cha opens up just about every dialog option... except a few paladin only, dwarf, or druid ones. Awesome seller/buyer as well. Nice Cha + use of friends spell.

Dwarf: fighter/thief. 17 max dex doesn't hurt thief skills too badly and IWD doesn't require a really excellent thief. Plus bard handles pick pocketing.

Elf: cleric. Good aligned.

Halfling: fighter. Helm of the trusted defender. Items to compensate for low strength.

Gnome: mage. Non-specialist. You'll be sharing spells with the bard, so you could go illusionist if you wanted to, using the bard to scribe spells the gnome cannot.

This provides a pretty well rounded party with thief skills (dwarf, half elf), great spellbased firepower (bard, mage, druid, cleric vs undead), good tanks (halfling, dwarf, human if dualed to druid at level 7 or 9), great summonings (druid ones rock, and you have the mage/bard to cast, plus ability to use items) and decent healing (cleric to start, eventually druid and bard). A weakness is the amount of healing early on, but potions and good use of ranged weapons can help avoid needing a ton of healing spells. Later on, healing will be a non-issue due to having 2 characters that can cast heal (cleric, druid) and the bard's War Chant. The main weakness of the party will be hold type spells... if that hits your cleric, you've got nobody to bail you out. However, a good aligned item exists that can remove paralysis and any cleric scroll can be used by the druid. The druid's ability to use cleric scrolls will also be useful if you need to ress your cleric.