OK, since you asked me specifically in that other thread. A few recommendations:
First, Tutu and other mods:
(1) If you're going to play with many BG2 mods, I'd consider re-installing from scratch after you finish Tutu and re-creating your character using Shadowkeeper instead of importing her. Importing from Tutu saves has some bugs on a clean BG2 install, so I assume that Tutu leaves some traces when you convert to BG2 - and you don't want that for a multi-mod configuration.
(2) Ascension and Tactics are, as far as I know, completely compatible. But read my notes about the kits in the other thread.
Your portagonist:
If you want a single-class rogue who never duals to another class, I think the Assassin is a very good choice. Most Thief kits max out in Thief abilities around level 20, so it really doesn't make sense to play a single-class Thief in TOB, but the Assassin only gets 15 points per level, so it makes at least *some* sense to not dual-class him. The Swashbuckler is as much of a fighter as a Thief can get, but his THAC0 bonuses doesn't really make up for his bad THAC0 progression. He gets 1 per 2 levels, so you have a THAC0 of -1 at level 30. That includes the kit boni. And he can't backstab. His AC bonus is great, though.
Personally, I'm not a Thief player (excepting the game "Thief", of which I'm a rabid fan), so you should take this with a grain of salt. I'd rather play a multi-class Fighter/Thief, or the very unusual Cleric/Thief.
Your BG1 party:
My most general rule for BG1/2/TOB party composition:
BG1 is the ranged fighters' game
SOA is the mages' game
TOB is the melee fighters' game
So, what you'll want for BG1 is a party with competent archers and slingers, and some mage power for the endgame. Your list has three spellcasters, which is too many for BG1 since their power is so very limited yet. My recommendation is:
You (Thief, maybe Assassin or Swashbuckler)
Kivan (excellent archer, is also available as an NPC mod in BG2)
Kagain or Minsc
Xan or Dynaheir (changed to Sorcerer)
Viconia or Branwen
Edwin
The archer: Kivan
My favorite BG1 NPC. *The* archer. Give him the Bracers of Archery, and between his DEX and his elven bonus with long bows he can hit almost anything in BG1 with his THAC0 of 3. He regularly gets 40% kills in my BG1 games where I don't play a fighter myself. I don't recall if you can change his kit with Tutu, maybe you can give him the Archer kit. I wouldn't do so, because he loses his ability to wear heavy armor, and as opposed to BG2, there's no Shadow Dragon scale armor in BG1. Unmodified, he's also a good tank.
Kivan is also available as an NPC mod for BG2, including a plot twist that may give you his one-time lover Deheriana as a party member. I haven't played this mod so I can't comment on it, but it does sound quite interesting. It may also be that it's not yet out of betatesting. Information at
http://www.gibberlings3.net.
The tank: Kagain or Minsc
Kagain is really the best tank with his CON of 20. But it makes more sense in terms of the plot to select Minsc. And he's the better archer, which is important for the BG1 part. It all depends on your style. When installing Tutu, you can change Kagain into a Berserker which is quite useful with all the mind-affecting spells flying around in the later parts of BG1, and without BG2s collection of immunity items.
The Sorcerer: Xan or Dynaheir
When you install Tutu (or maybe a Tutu mod, I don't recall exactly), you have the choice of changing almost any BG1 mage NPC into a Sorcerer. I recommend Xan, who has, as an enchanter, already the high CHA. But you can really have anyone as a Sorcerer. I would select Dynaheir for this slot if you select Minsc for the tank, since that makes more sense in terms of the plot, right up to the start of BG2. Else, select Xan, if only for the simple reason you probably haven't played him before - as a Sorcerer, he's not useless at last. Make sure your Sorcerers learn Identify if you intend to play with Edwin. There aren't many good L1 spells, and gold is extremely scarce in the first chapters of BG1.
The Priest: Viconia or Branwen
No single class Druid in BG1, I'm afraid, not even in a mod. Viconia is, again, the best choice for the primary cleric slot. I don't recall where the Gauntlets of Ogre Power are in BG1 right now, but they are there and as useful as in BG2. Branwen is also a good choice. I haven't used her with Cleric Remix yet. As opposed to Viconia, she may actually gain something from it since her god, as a deity of war, would grant more buffs and healing spells.
The Wizard: Edwin
You can change him into a sorcerer, too, but you also need some variability in spells, so I wouldn't recommend that. For the *best* Wizard type, there really isn't another choice that's nearly as good. His only disadvantage is that he's evil, but since you want a neutral party this time, he would work well.
So much for your BG1 party. now onward to BG2:
Your proposed party has too little mage power. I'd recommend something like this:
You (Assassin or Swashbuckler)
Viconia or Anomen (the CN version)
Edwin
Korgan (but he can't wield Azuredge. That's a *big* disadvantage!!!)
Nalia
Valygar (change as described below, dump for Solaufein in Chapter 6)
This way, you have three frontliners and three mage slots (you'll be thankful for them soon, especially with Tactics installed. Be sure to read Userunfriendly's cheese guide!).
Not much to add here that I haven't yet said in the other thread. Change Valygar's proficiencies so that they include axes. The big disadvantage is that you have no one to wield Azuredge once you acquire Sola. But if you do most SOA optional quests in chapter 2-3, it may not be that important since there are not so many undead left, and TOB hasn't nearly as many as SOA. Improved Bodhi may give you a headache, though.
Again, I really don't understand what people find with Haer'dalis.
So much for now. I have some RL to attend to...