Agree with Octavius: you want a multiclass thief, as single-class thieves suck in GB, and a second dwarf fighter or fighter/cleric isn't that useful--you definitely want another mage.
Human Knight, Dwarf Fighter, Elf Fighter/Mage, Elf Ranger/Cleric, Kender Cleric/Thief, Human Mage sounds reasonably true to your original ideas. (In particular you seem to like having a variety of races in your party.) I might change your dwarf fighter to a human paladin so you can turn undead in Death Knights.
Krynn party design is a different story than Pools series/Savage Frontier party design. Demihumans are useful, and muticlassing is as well. Also, you want to have both good and neutral mages as they get different spells, and in some cases both good and neutral clerics as well. In addition, Death Knights of Krynn has a higher need for clerics than most games due to the large numbers of undead. The game is tricky with less than three. I also take the contrarian position that a single-class mage is of great value in Dark Queen of Krynn, as there are numerous enemies with 50-90% magic resistance (MR), some which are spellcasters. A dual-class mage will level into the twenties, a single-class mage into the thirties by the end of Dark Queen--this will make a HUGE difference when you drop those fireballs (MR is calculated at 11th level for the caster, plus or minus 5% per level of the mage.)
Warning: do not use female demihumans as any type of fighter class (fighter, ranger, paladin, knight), you will run into strength limitations.
Warning: demihuman level limits are much laxer than the other games, but they still exist and can blindside you in later games. Elves can reach max level as clerics, rangers and mages, (and thieves for the Qualinesti), dwarves as fighters, half-elves as clerics and thieves (but can't be cleric/thieves for some weird reason, nor can elves), and kender as thieves. (So a dwarf fighter/cleric isn't a great idea...have the kender or half-elf pick up the mixed class instead). Kender in particular have very low level limits as fighters (5!).
So you should be looking at human knights, paladins, clerics, or mages, elvish fighter/mages, ranger/clerics and cleric/mages (or fighter/cleric/mages but this advances slowly in later games), dwarvish fighters, and for your thief you can go kender cleric/thief. Kender are limited to 12 as clerics, but what else are you going to do with that thief slot? (And you need a thief to finish one particular part of Dark Queen.) They also get the taunt (YELL), which makes enemies target them rather than more valuable characters, and are kind of a fun extra option you don't get in the other games.
Cleric god choice is a bit less of an issue. There are good and neutral gods, clerics of Majere turn undead as two levels higher, Mishakal get bonuses to healing, and Kiri-Jolith get a small THAC0 bonus. (All of these are good gods.) Also, clerics of neutrality get higher-level spells a little earlier--this is useful in Champions (where they get Hold Person at 2nd level) and Death Knights (where they can get access to 7th level spells, unlike their good siblings). Also, a 12th level neutral cleric gets 7th level spells but a good one doesn't, so neutral cleric (I like Shinare for the Charm Person spell) is a good pick for your kender.
EDIT: kenders are limited to a 16 wisdom (no 6th or 7th level spells), so you may want to use this one as Majere (turning maxes out at 14th level, but 12+2=14; I can confirm 12th level Majere clerics act as 14th level for turning) and make one of the others a neutral if you want 7th level spells in Death Knights. Neutrals still get more 5th level spells, which is somewhat useful. It's kind of a tough call.
Red and white mages offer 2 choices but relatively higher stakes--they have different spells. Generally white mages get the debuffs (Charm and Hold) and defensive buffs (Minor Globe) and red mages get the offensive buffs (Mirror Image, Haste, Fire Shield), but there is a lot of weird overlap (Reds get Invisbility, Slow and Fear) and generally you need one of each. Red Robes get Fireball at 4th rather than 5th level, so if you have a single and a double-class mage there is a case for making the single a red mage. (Whites get delayed-blast fireball at 11th instead of 12th, but as this is less of a game-changer it is less of an issue.)
I'd say you need three clerics, two mages (one red and one white), at least three (preferably four) characters with a fighter class, and one thief. That's 9 characters, so multiclass as above. Knights can't multiclass but get Solamnic Plate and there's a quest in Champions you need a knight for, so putting a Human Knight in front is reasonable.
I beat all three with:
Human Knight
Elf Ranger/Cleric (Majere)
Elf Ranger/Cleric (Mishakal)
Kender Cleric/Thief (Kiri-Jolith; I would use Shinare)
Human White Mage
Human Red Mage
This had the disadvantage of not having seventh-level spells accessible in Death Knights, but demolishing draconians with delayed-blast-fireballs made up for it.