Zufari was great - we went at the height of summer though, hot temperatures and bright sunshine lent it a very authentic air! Can imagine it might be a bit miserable on a dull rainy October day, not sure how they'll persuade all the animals to be out. We had fast passes and still ended up queuing for 20 minutes. Unless they've changed things since July there is nothing to do in the queue but stand and wait so it's really rather dull, just to warn you.
Re cheaper entry, I know South West Trains had an offer where you could get discounted entry if you showed your train tickets, and there's been free entries on Mini Cheddars in the past (not sure how recently though).