New to BG1 - Party set up/dual classing.

Hey guys I'm new to BG1 but i've played BG2 quite alot during my teenage years. Can you give me some advice regarding party set up and dual classing.

I'm thinking this time round, i'm going to roll a human fighter/thief dual class.

What level would you recommend i should dual class and weapon proficiency i should take.

Also thinking my party set up would be:

Kaigan - tank
Minsc - bruiser
Viconia - healer
Edwin - mage

6th character slot could be Imoen thief/mage or a ranger npc.

What do you guys think? Also what should my alignment/reputation be to keep my party from leaving?

I bought the enhanced edition from steam, could i port the saved game over to BG2?

I'm sorry for so many unstructured questions, i'm just listing them as they pop into my head.

And as always, thanks for all the help/advice.