Merchant?

Korevac

I just had a idea! I'm going to go through the Saga as a lawful evil/lawful neutral greedy merchant.

Someone who doesn't care for psychical or divine/magical prowess but is just intent on gaining as much money throughout the game to buy his own private island. I don't know what race n class would best represent this, I want to go dwarf or gnome or halfling just so I can be visibly fat, but then that leaves out a lot of classes. obviously he'll need the finest (possibly cheapest) bodyguards the sword coast has to offer so I don't know who would fit the role best?? Shar-teel, Minsc and Dorn probably up their with the best and Branwen wouldn't even expect payment hmmm....

Sharguild

Storyline may require more from you than you intend.
As a standalone scenario, ignoring the storyline, certainly possible though.
Obviously you need the muscle and spells to pull it off so having the other 5 party members selected appropriately will be key.
Easy enough to do, go with folk you like. You can absolutely win the game with almost (almost) any party selection. Taking yourself out of the mix as a combatant though could be tricky. One of each type class as minimum I would suggest and use the tomes on party members, not yourself. Same with any gear other than protective ( maybe give yourself a dagger for those moments when dying is inconvenient).
A fat gnome fighter would probably be easiest to create to stay in character. That would give you opportunity to wear protective gear without giving you excuse to engage in combat. Your excuse can be a variety of roleplaying scenarios.
Best of luck to you. Interesting idea.

Merina

A fat bard. You can always choose not to have him learn spells.

If a fighter, a Kensai would force you to not wear any armor. If a normal fighter, imagine unusual weapons such as a Club, Fists only, at most two Daggers, or a single more exotic "good-looking" weapon.

Not sure Minsc fits well into the story then. He's looking for help and doesn't even offer bodyguard services to anyone other than Dynaheir. Dynaheir isn't anything likely friendly or thankful early on when freed. She will stay with Minsc, but Minsc is anything but a mercenary who wants to earn gold.

Kagain ... with his shop and business ... is more of a mercenary and willing to give up his own shop even.

Safana ... looking for treasure, but planning to become the leader herself.
Coran ... similarly, but doesn't want to be leader.

If neutral, the merchant might persuade Ajantis as bodyguard. Branwen is a good choice. She's thankful for the rescue at least.

If evil, Viconia will likely enjoy serving as a bodyguard ... she's quite desperate early on.

Anduin

Go Gnome. They enjoy collecting trinkets, not necessarily just gold and gems.

If it is just gold and gems... Go Dwarf.

I suggest a Cleric of Tymora.

Or possibly a rogue. A shadowdancer may be good... Many characters, Volo for instance, were very good at disappearing at the first sign of trouble, without any mystical training...

lroumen

Garl glittergold?

Sharguild

Putting thought to this, A Gnome Illusionist would serve well. You've obviously decided to become successful by virtue of some trait and what better than illusion? ( The Forbes 500 use it everday!)
You can protect yourself by a variety of illusionary magics and call in summons to protect you when needed. You depend on force of arms of your mercenaries as required. Hell I might role one myself.