Does anyone know how exactly rent control currently impacts the above three arrangements?  

A percentage is always good, so long as its well managed, to ensure its an equitable arrangement for all.

Is there potential to use it for AirBnB or some other short term arrangement to increase the income?

Now, he reported the dishwasher is dead, and that still has the gas smell in the bathroom (from the missing P-trap), so he was going to make arrangements to solve the problem soon and deduct it off his rent. 

In a large minority of cases, the tenant pays both agents.There's no strict guideline and the commission arrangements are certainly not governed by law, except that any commissions paid by the tenant must be disclosed in writing and have the tenant's signature approving it.If you rent it yourself and have signed an "Exclusive Right To Rent" agreement with your agent, you will still owe the commission.As an aside, I try very hard to stay away from rentals.  

(Be clear: If it's a commercial arrangement with people you didn't know before, they're NOT "private money lenders"!)...

She has arranged inspections, repairs, found us great tenants, and helped us find valuable properties. 

Also, you need to be aware that if you continuously accept partial rent, say 3-4 months in a row, you may tacitly change the due date of the rent based on the arrangement, which could ruin an eviction if you demand the full amount based on the written rental agreement grace period.

Brendan Harrison Listing agreements are contractual arrangements between the listing agent and the seller...The seller pays the commission, so if you don't use an agent it doesn't improve your position.

For example if you owned your previous home, had plenty of equity, worked out a forbearance or deferment arrangement with your current mortgage company, the mortgage on the new loan was less per month than renting in your area (common in Houston) and truly have a plan for exiting the old house, as in you have the means to repair it or the equity to be able to let it go as-is and not be upside down.Or you are well within a floodplain, so you have flood insurance and you'll have a payout, maybe you've flooded before, and and it's just time to move to higher ground.