split stay park ticket question

[westgrove]

Hi, following the success of my 1st WDW holiday this year I've been planning for next year. We're looking to go in sept/oct for the food and wine festival and halloween.

I'm thinking to booking (DIY);

-return flights to MCO
-Coronado Springs for 12 nights with 21 day park tickets
-a hotel in Clearwater/St.Petersburg for 4 nights
-Art of Animation resort for 4 nights (possibly a different resort if any good offers come up!)

I'm hoping to get FD for the 12nights at CSR if the offer comes back up and if I do I know the rules that this must be fully used up before the end of your check out day,

however,

I do not know how park tickets work? if i buy the 21 day park tickets but my CSR reservation is only 12 days does my KTTW still stay valid for park entry for the remaining 9 days after check out?

TIA, Laura