If I deactivate my account, and kater I choose to come back/reactivate it

Yea. Nothing goes away or is lost in going on hiatus/deactivating.
This is different from [i]canceling[/i] your account which is a follow-up action to deactivation (if you log in and click the button to cancel rather than reactivate).
Edit: also, in the last part of deactivation, you can choose to have your profile still viewable or have the X over your pic and not be viewable.

I've gone on hiatus/deactivated many times.

Thanks guys

Yes

I've deactivated a few times. I didn't lose anything, as far as I know.

Sometimes they dont allow you to delete.

I think you lose some coins

Yes

Yeah