Hey, nope. You can’t release a big project and then “unbundle it” into smaller projects, just like you can’t release small projects first and then also try to bundle them up and resell as a “bigger pack”. You either pick one or the other option.
That said if you don’t want to sell your big pack anymore, you can delete it from the marketplace and then you can submit each different animation from that pack as a separate project. And vise versa.
But if you were to take your bunny and create a new, unique logo reveal animation with it, it probably would be seen as a new project. Think of it this way if you take your old assets and reuse them in other projects, in a way that the end result looks 80% like your old project - ehhh you might get rejected for submitting derivatives of your previous work. But if the result overall looks at least 80% new and different you should be good. As for everything in between - you risk getting rejected.
That said the percentage threshold for what is new or old is very subjective And you will see lots of items on the marketplace with different variations of newness/sameness.