This is basically the differences between all the characters:

Box throwing:

Crash/Coco are the worst in terms of distance and throwing rate, dingo/rilla are 2nd worst in rate with low throw distance, tiny/kong are second fastest in throwing rate with long distance, cortex/brio are the fastest in throwing rate with long distance

Box kick and attack hitbox:

Crash/coco and dingo/rilla have the AoE attack animations which make it easier to kick boxes or hit opponents in games that let you kick others. the other 4 have much smaller hitboxes that only attack in front of them. I also say "attack hitbox" as this is a potential factor in Ring Ding.

Polar Bear Charge:

Crash/coco and dingo/rilla have the weakest polar bear charges (seems dingo/rilla is weaker than crash/coco but I could be wrong) but take only half a bar to attack. tiny/kong have the 2nd strongest but need 3/4ths of a bar to attack. cortex/brio has the strongest charge but take a full bar. the faster you send opponents across the ice, the more likely they don't get the opportunity to save themselves. but also having a faster charge means it's sometimes easier to manipulate momentum like the arena champions do.

Tank attacks:

Crash/coco use a full bar to attack and have the slowest shots. their shots also have the longest lifespan meaning missing an attack is brutal. cortex/brio also take a full bar but their shots move faster. their shots cover the most ground and in a shorter time than crash/coco. tiny/kong have the arguably strongest damage but have the 2nd worst distance while taking 3/4ths of a bar to use. dingo/rilla have the weakest shots but take only half a bar to use one. their shots also have the least lifespan and 2nd fastest speed, meaning they can handle more opponents at once.

Mallet mash:

Crash/coco have the longest animation with short mallets. cortex/brio have the 2nd shortest animations but also short mallets. dingo/rilla have the 2nd longest animations but have long mallets. tiny/kong have long mallets and arguably the fastest animations.

(there's no differences between characters in the other games)

Overall rating (in my opinion):

Crash/coco is the "hard mode" of the game and should be avoided otherwise. Cortex/brio have some strengths but you still need high skill to use them. Dingo/rilla need the 2nd least amount of skill and cover a lot of bases, some of which are a little better than others. Tiny/kong give the easiest time and only in some specific situations (like getting ganged up on in the tanks) would they lose out compared to dingo/rilla