Well....
yellow> more grab and smash range, more hitstun (why i usually use it for dthrow set ups... if yellow is used for dthrow, the extra hitstun nearly always allows for a fair..... then fastfall regrab
[doesn't alway work lol]). most priority even through marths fair, flies in an arc shape...
Red > powerful fair used for side kos, ok priority, randomly powerful dthrow after a certain % so noy used for comboing lol... good knockback.
blue > what u said, can survive in water, powerful usmash, iffy priority
fatty > wat u said, good priority when thrown, very good usmash, toss can be follwed by fair... no escape....,
white > wat u said, further grab and smash range (i think), set up bringer ie, weak smash can be followed up by another, or an aerial etc.... flies fastest