Shoot, I didn't realize the MRPP chat went down..
Oh well, might as well retype what I came up with.
Wheelie - Actually rather innocent and childlike, mostly a part of the coalition out of sheer boredom. Eager and fast talking, but not too bright. In fact, he tends to forget large details and has a short term memory. Easily distracted.
Toad - Drastic overachiever. He's sick of the way of the royal guard, who simply try to look intimidating by holding large spears and shields they cannot actually use. He's out to prove his ability, and he has the heart to do it. However, he's also a bit of an outcast within the Minion coalition. He's still a Toad and doesn't enjoy doing some of the darker things that the group plans, sometimes hindering everyone else when he's involved.
Bob-Omb - Somewhat tempermental and controlling, Bob-Omb is actually a very capable leader. He's certainly more capable than most of the other minions, dispite his egoism. He tends to be very violent, foul-mouthed and critical, but otherwise is actually very good at organizing the team's thoughts when calm.
Piranha Plant - Slow talking and lazy, Piranha Plant is actually a sleeping genius. With the right motivation, he actually comes up with very good plans to get the group what it wants. He mostly comes up with his ideas in the middle of a meal (which should be something just off camera, and outlandish sounding like "fried pygmy Turkish delights"). As far as being a team player goes, he's not very willing, somewhat whiny, and has trouble communicating with the others due to a thick foreign accent.
Hammer Bro. - A member of the most elite sect of the Koopa Troop, this Hammer Bro. deserted due to being the best of the best there is. Tired of constantly showing up his comrades, he decided to take them all on at once. He's the most physically capable of the group and is certainly not afraid to show off. However, he's also easily distracted in the name of competition. He's quick to go off on his own plans instead of those that the others agreed to, hopeful to prove himself. Obviously this keeps screwing up, and eventually should put a damper on his self esteem.
Waddle Doo - Like Bob-Omb, Waddle Doo is eager to lead. However, he's much more apologetic and clumsy than the former while being more level headed. As a team player, he tries his best to be helpful, which he can be. He has his moments where he can be quick witted and even crafty, but often times this oppertunity doesn't stay open long enough and messes him up in some way. He's also the only one who can consistently understand Piranha Plant.
Waddle Dee (if we get one) - A rather stock character who can only say "Wanya" and requires translation via Waddle Doo. He's shy, somewhat cowardly and obviously lacks communication with his team members. The only reason he's tolerated is due to his speedy and effective physical labor skills. Eventually, he should start to learn some English, albeit incredibly broken.
Biospark - While he wants to be a stereotypical shadowy figure, he's an extremely large ham. He speaks bombastically of his ability and feats of strength and occasionally speaks in (poorly written) haiku. As far as team participation goes, he tends to vanish at the first sight of danger, coming back later with some outlandish excuse that everyone buys. At one point, he should have an extremely cheesy theme song written for him ALA Bang Shishigami that plays as he actively does something (and fails).