For the son to qualify for the $250k exclusion, I believe he would most likely need to meet the ownership and use test, meaning he needs to own and live in the home as his primary residence for at least two of the last five years before the sale.

The National Association of Realtors.That said, I will not be signing an Exclusive Right to Represent as an established real estate investor, and I’m honestly a little annoyed to be asked.I also realize this may qualify for Reddit’s AITAH channel.

The capital gains exclusion is available to owner occupants primary residence.

You don't have to sign the agreement, though some state laws require an exclusive contract.

I've had qualified renters move into a rental, add their bum friends or family members, and then disappear, leaving me with bad renters who weren't approved and aren't on the lease.The best practice is to screen every adult, approve them, and add them to the lease. 

It has nothing to do with marital status or one's relationship with other adults.

Quote from @Victor Yang:In addition, is it possible for me and my wife to gift 36k worth of equity per year of the house (under the annual exclusion limit) and therefore have none of the costs go towards the lifetime gift limit?

guests=1&adults=1&s=67&unique_share_id=6413afb1-1f4f-465e-9828-521b480103c3

guests=1&adults=1&s=67&unique_share_id=1ad32050-c8a3-4f7e-95e9-ce2c43297af8

Every adult should be fully screened to ensure you aren't renting to a violent criminal, drug dealer, etc.