So you know those pets that say you can regenerate all colors or this amount of trait points. How does that happen? Is it just random or is it like wow this pet got to 50 generations heres a special pet? Is it dictated on how long the pet is alive for?

see: guide to regeneration and revamps

basically, regeneration is because something fundamentally changed about how the pet was set up when they were revamped, eg, traits getting moved to a slot that clashes with a trait they already had, mutations or genes that were only in one slot get split into, say, a head and a body section, etc.

It only applies to pets born before the revamp who fall under the regeneration parameters of that revamp

Colour regeneration can be made available if Krinadon alters the way in which certain traits are affected by the colour slots, eg, the recent allowance of vulnyx with arctic nomad mutations to regen AC2 (since they previously used a different slot to control parts of those traits, but Krin swapped it to using AC2)