For Vanilla MM7 the best balanced party is probably the default party of KTCS. My favorite melee heavy party is KMTC. The only disadvantage is you don't have utility elemental magic but there's ways around it. My favorite magic heavy group has 2 sorcerers a cleric and one other character. Normally either a Druid, Sorcerer, Thief or Archer for the last character. Sparks is a good spell for an Archer as they don't have much spell points and does decent damage for low spell points. If you don't have a dedicated thief I'd recommend either having someone master Earth so they can disarm the trap, or just let them blow it up and heal yourself with GM regeneration. For skills if your going light I'd recommend concentrating on learning, Body, Light, Merchant, and Water. If your playing a magic heavy group Water and Merchant are most important as you need GM Merchant and Enchant Item ASAP as all those spells cost a lot of money and you don't find many spells other than on Evermorn Island. Melee heavy parties don't need as much money.

For the BDJ Mod I recommend my Melee heavy party of KMTC, or KKTC and later multiclass them into hybrid/magic classes. That way you have great melee damage and fairly good magic damage/skills. You also get access to both Light and Dark Magic up to Master level.

For the Maestro mod my favorite party is DCSS. Later on you can promote everyone to Liches and get Dark GM. I'm not sure if all characters can be turned into liches or only certain characters? With high Light magic buffs you do fairly good damage. I think my sorcerers did about 80 damage on hit. So most of the weak to medium monsters you can melee and the stronger ones you can use Shrapmetal and Soul Drinker on. Certain areas like the tunnels to EOFOL and the Maze are easier with a magic heavy party.