Hemaka: Hello Pfreaker.
As far as your party setup goes I can see some slight issues:
1) focusing on con with samurai - it's not useless but samurai is propably going to be one of your damage dealers (and certainly not a tank) so I'd rather develop str/dex first (and later speed/con or speed/senses if you'll find out that you don't need that extra HP or iron skin further in the game)
2) I assume that you want your fighter to be tanky (using shield and bumping con to 100) and that's ok, just after maxing these two put points into dex - after all he's not gonna be a FIGHTER if he can't hit anything :P besides it's very powerful class in terms of dealing damage so it's worth it
3) keep in mind that developing good ninja is going to take a loooooooooooooong time (and if you want him to be a backup caster even loooooooooooooooooooooooooooooonger) - he needs a lot of attributes/skills on high level to shine with ranged criticals and/or spells
4) it's your choice obviously but priest is imo the most useless class in unmodded wiz8 - all his spells can be cast by either combo of gadgeteer/bard (and they fight better too and also have many offensive spells) or bishop with 2-3 schools; so I strongly suggest thinking about dumping priest and taking bish focused for example on divinity/psionics (cause you don't have these schools on other characters) or even better divinity/psionics/alchemy (yes, 3 schools bish is easliy done if you remeber to cast a lot in and out of combat)
Of course with your party you're propably not going to have any problems beating the game (especially if you'll take any rpcs with you later on) but maybe on second playthrough you'll find these few points helpful.
P.S. I strongly suggest letting all willing npcs to join your party on your 1st playthrough - they add a lot to immersion and depth to the world you're travelling through.
Here are my thoughts on these:
2. Fighters already get more HP than any other class; they don't need more. Remember that healing does not scale past 70 points average until you get Restoration, and even that spell is single target.
4. I disagree: Priests get more HP than other pure casters and can be surprisingly good fighters if you max STR and (I think) DEX. Unlike other pure casters, Priests do not need Power Cast. One interesting option that I actually did once was to learn most of the important spells and then change to Lord. You will stop progressing in Priest spells for 4 levels if you do this, however. Also, remember that Priests can pray once per battle (it's easy to forget about it) for a random beneficial effect.
I actually consider mage to be the worst class. If you need mage spells, Bishop works well. Bishops get more HP then Mages and have a much bigger potential selection of spells including such spells as Toxic Cloud (damage + status ailments over time) Psionic Blast (damage to a group, ignoring line of sight issues), and Quicksand (instant death to an area that is especially effective against flying creatures).
Of other note, Samurai can learn Missile Shield and Enchanted Blade, which are the only two mage spells that you *need*. Armorplate and Magic Screen are the two Priest spells that you *need*. If you have those spells plus Heal Wounds, you can do without other spells (though having a Priest or Bard for Heal All is useful.)
By the way, if you ever make a Bard or Gadgeteer, make her female. There are stamina regen items that can only be warn by women, and those two classes use stamina for their spells.