Yes. Cinema Buff's speed up whatever you land on. Say you land on 50% plants. They grow twice as fast.
Try to buy as many Treasure Hunters as you can. They can be very helpful in getting items you need When you trade sets in.

Secret Island treasure locations

Zombie castaways treasure locations .

Re. Big Island. You have to tap on mountain top and then it will want you to buy it with coins or zombie bucks.

Help please. Finished all castles on star island but am locked out of one remaining section in left center of island. Is this part accessible? If so how to unlock? Thanks