We have a customer that is a real estate rental property management company. Nothing on their web site indicates that they are involved with brokering or real estate sales, they are merely a management company for rental property owners. Assuming they meet all other criteria for exemption, does this sound like their type of business activity would not preclude them from being eligible for an exemption?

While it is possible, it will probably come down to how comfortable you are exempting a third party payment processor.