If you have to make up people, realtors are fairly ideal in that they don't work cooperatively. Mostly they try to shut each other out. So it won't bother other realtors that they have not heard of this one.

Realtors should have state-issued licenses as real estate salespeople. Actual "REALTORS" are also members of the National Association of Realtors, so they should be listed there. They should also leave footprints in the transactions they close successfully, since at the closing they receive checks from sale proceeds, but I'm not sure where to look in public records.