Well the story written by Kevin and Peter about the Turtles going to a fancy dress party at April's and ending up beating up some thugs and trashing their costumes so going as themselves may well not be canon.However exerts from their origin is in their and that is canon, the characters created purely for the game are not canon but they do have the Eastman and Laird signature against each one of them.
OK back to the stats
IQ - Intelligence Quotient 16 or above is exceptional so Raph and Mikey are average intelligence, Leo is highly intelligent and Don is a genius!
ME - is Mental Endurance is shows how well a character stands up to mental attacks and Psionics and their potential to develop mental powers again 16 or above is exceptional Leo's focus is shown in this stat and he's resistant where as the others are on the high side of average.
MA- is Mental Affinity it shows charm and charisma, 16 or higher is exceptional, so Mikey with 19 is the most charming and charismatic with Leo being high there too which shows he's a good leader, Don and Raph are just average
PS= is Physical Strength 1-14 character can lift 30 times their PS 15-19 means the character can lift their PS times 40 20-23 can lift 60 times their PS 24 or higher can lift 100 times their PS so Leo would be able to lift 600lbs so he's approaching peak human according to the game, Mikey is 640lbs so slightly Stronger Raph, can lift 1200lbs so he is slightly superhuman in strength and Donny is in at 390lbs.
PP - Physical prowess this is the characters agility and dexterity 16 and above is exceptional and all are above 16 but Mikey owns with 24!
PE - Physical endurance, stamina and durability all apart from Donny are above average but Raph is the most durable and toughest according to his stat
PB - Physical beauty 16 and above being high, as you can expect they're turtles so only Mikey gets a high score and this is based on him being loveable and funny rather than good looking!
SPD - Speed this stat times 20 is the number of yards a character can run in one minute Raph is the fastest at 300 yards in a minute, then Mikey with 280 then Leo with 200 and finally Don at 200 yards in a minute.
Raph in the game was basically a brick, tough and strong and able to take more damage than the others Mikey was the hardest to hit and could block hits and strike better than the others and Leo was somewhere in between the two, the best of both worlds as it were.
When we used to play as kids NO ONE wanted to be Don! lol