Knight: Prime stat: Might.
Best fighter and can use any weapon or armour. Starts with the Arms Master skill, can't cast spells.

Paladin: Prime stats: Might, Personality, Endurance.
A good fighter, but not as good as the Knight. Can use any kind of weapon or armor, but his hit points are lower than the Knight’s. Starts with the Crusader skill and can cast Clerical spells.

Archer: Prime stats: Intellect, Accuracy.
Not quite as good a fighter as the Paladin. Can cast Arcane spells, but is limited to wear armour chain mail or lighter, and can't use a shield.

Cleric: Prime stat: Personality.
OK as a fighter, but is can't use edged or missile weapons. Can use splint mail armour or lighter and has twice as many spell points available for casting Clerical spells as the Paladin.

Sorcerer: Prime stat: Intellect.
Very poor fighter. Can only wear padded armour and can only use staves and daggers as weapons. An Arcane spellcaster with lots of spell points. Starts with the Cartography skill.

Robber: Prime stat: Luck.
Another OK fighter. Can use most weapons, but is limited to chain mail armour or lighter. Can't cast spells. Starts the game with a Thievery skill of 30.

Ninja: Prime stat: Speed, Accuracy.
A decent fighter, but can only use ring mail armour or lighter armor and can't use a shield. Can use most weapons, but is best with the Japanese ones. Starts with a Thievery skill of 15. Can't cast spells.

Barbarian: Prime stat: Endurance.
Next best fighter to the Knight, but limited to scale mail armour or lighter. Get most Hit Points and gain extra attacks . Can use most weapons and shields but can't cast spells.

Druid: Prime stats: Intellect, Personality.
Very poor fighter. Can use only light armour and weapons but can cast Natural spells and a few Arcane and Clerical spells. Start the game with the Direction Sense skill.

Rangers: Prime stats: Intellect, Personality, Endurance, Speed.
The "Jack of All Trades" - good fighters, can use most weapons and armour, and can cast the same range of spells as the Druid. Start the game with the Pathfinder skill.

Comments
1. I don't use ninjas. I tried one, but I found their initial Thievery skills inadequate, and my party kept getting blown up. Neither did the Thievery skill advance quickly enough, and my party kept getting blown up.

2. I always use a ranger. Only the ranger and the druid can cast the "Walk on Water" spell, which is essential for exploring the deeper seas.

3. Initially, certain skills are restricted to particular characters, (e.g. only the thief and the ninja have the thievery skill) but there is a way that a character can learn all the skills.

4. A thief is essential when you first play the game, but once you find out how to give a character all the skills, (expensive, but highly recommended!) you will find that the sorcerer makes a very bonny thief.

It is important to learn some skills reasonably quickly. For example, you need the pathfinding skill to explore the woods, the mountaineering skill to explore the mountains, and you need the swimming skill to explore the various ponds you will find and the stretch of sea next to the land. All your characters will need to learn to swim, but IIRC it suffices if one character knows pathfinding and the two front characters know mountaineering, so save your money!

Balanced parties
I have a personal preference for magic-heavy parties, so bear that in mind during the following comments. My preferred party is knight paladin, ranger, archer, cleric, and sorcerer.
(1) Cleric and sorcerer for the heavy-duty spell-casting,
(2) Sorcerer and archer so that the party can cast two Lloyd's Beacon spells (essential if you want to bounce back and forth between two places),
(3) Fighter and paladin for the melée damage they can do and for booting down doors,
(4) Cleric and paladin so that you still have a good healer if one gets knocked out,
(5) Ranger for the spells Walk on Water and Nature's Gate, and for backup in melée and healing, and
(6) Archer for backup in melée and his ability to cast the full range of Arcane spells.

But like I say, initially you need a thief.

The effect of stats on abilities is very like MM6, and you have that right.