I have not been renting the property long enough to have proof via tax returns (they always ask for them) that they produce income.

Place the burden of proof on the "good" tenant to get the bad egg out and find someone who can and will perform.

My real estate attorney said it is illegal in Pennsylvania to ask potential tenants for pay stubs as proof of income.

You might have difficulty getting a loan however if you don't have proof of income.

Are sellers really accepting offers or even hearing them without proof of funds?

If they ever do, or a situation arises where I instruct them to read their lease, you need to make it as idiot proof as possible.  

would the member be a wholesaler maybe and the end buyer backed out.. did you get a POF  ( proof of funds) or any type of clear to close from the lender

Did he have an LLC in the US, and Proof of Funds that he could send you?

I left a message saying I hope they didnt get the dog and would look into the legal process of handling the situation, and to please call me back.So I have no proof they have gotten the dog, although it seems pretty clear.

Everybody says they know where to find it but no one has any proof it exists.