1) I know there is a CAM bank in Sucina, but I dont know the town well enough to know if there are other. Unless someone actually knows, I suggest you look on the Barclays website for the branches in Spain.
2) Not sure if there is actually a specific Polaris World card, although there is a general PW 'owners' card on which you get discounts at PW Garden and other PW places.
3) All the Polaris Golf Courses in operation so far (MMGR and LTGR) are 'open' courses (i.e.available to resident owners/renters and the public) but each course has a separate Residents/Renters tariff and a Public Tarrif for the cost of the round. I imagine this policy will continue as more courses are added....so there isn't really any need for an 'entitlement' to play on PW courses....anyone can book and will pay the appropriate green fee from whichever tariff. There are annual memberships (just as in UK) for around 1,900 euros for owners and there are multiple rounds tickets which work out slightly cheaper than paying multiple green fees. Green fees are about 55 euros a round currently on MMGR and LTGR.