I did a lot of the stuff on your list last year. If you don't have a car I would start at ceuse and work your way out from there. Put a note up on the notice board and you will be able to hitch a ride to more climbing easy.
Kalymnos with out a car is super easy. You wont need to but you can hire a scooter super cheap with minimal paper work.
Mallorca isn't do able without a car but if you find someone who can drive get there. I was there in july it was hot but perfect for DWS.
I don't know much about northern spain though sorry.
Let me know if you need anymore info.