For example incase iIf you identify an asset in the market that already has a realtor representation on both the buyer and seller side, do you reserve the right to proceed with the deal independently, or do you have to bring in your realtor? 

Ask the seller for repairs or walk away.

I recommended he talk to his parents about buying the house in an installment sale and using seller financing with them.

That satisfies the requirement that the seller and buyer be the same for your 1031s.Once you own the property as tenants in common you can either form an LLC and contribute the property into the LLC in exchange for membership interests respective to the amount you are contributing. 

Per the agent, ok to start rehab while seller still in there for a few days up to two weeks.  

Plus, the seller paid down the rate to 5.5%!

Are they good assets (A class, good location, high demand)?

The rental and homebuyer demand is pretty stable so it appeals to a lot of investors.

The rent declines in the market are temporary until the new supply gets absorbed and demand picks back up.

I say this because we used a different realtor to purchase our STR and it was a disaster all around - both our agent and the seller's agent didn't know what they were doing, had no worthwhile advice to offer, messed up paperwork so that it had to be done again, just a sloppy experience all around.