I was just playing and say i had 8 of the candy hearts and i wanna get atleast one pet from every event so pls help :<

getting a complete set of all 10 hearts and using them doesn't guarantee a theme- it's a much higher chance that you'd get an avatar item.
(there was a task during the Event where if you completed 8 sets of hearts you'd get a theme egg, but the event has ended so that's now a moot point)

But you can check the complete set of hearts in the week of love news post

Its a bit latebfor candy hearts, the event already ended. But dont worry youll be able tp get one next year.

You could also check what themes were up this year and buy one from the advanced search if you wanted to.

Unfortinately if i remember correctly those candy hearts won't be worth anything now since the event ended. Though i do know there are some candy hearts dti up on the trade broker.

Its also a very low xhance that youll get a theme from candy hearts too so its not garenteed, youre more likely to get an avater item or something.