Besides the funds availability disclosure, are there any other required notices that must be posted on an ATM for a bank that does not charge any fees to non-customers for balance inquiries or funds transfers? What if the non-customer's bank charges their own fee--any related disclosures in that regard?

You are not responsible for any disclosure of the non-customer's bank's fees. Network rules will probably require you to post network logos (but that's a contract issue, not traditionally considered part of the compliance "basket").

If you advertise any product or service you'll have advertising rules to consider.

Of course, there could be some state mandates.