I've never heard the 25% thing before, but any difference between FMV and sales price would technically be considered a "gift" with potential tax implications for your parents.You can avoid most seller costs as there's no reason to use agents in this case.As an FYI: I always recommend avoiding a FHA loan, if you qualify for a low-down payment conventional loan.

That agent is very smart! 

But I spoke with an agent earlier on a property and he gave me the NOI for last year for Airbnb on it

Your agent should have the experience to navigate this.

I see you're a real estate agent, but do you invest in real estate personally as well?

A lot of times it is best if the existing pm is the listing agent so they can negate this along with tenant communications. 

Rent would be ~1,400 to 1,800 / month which is above market rate but housing is in very high demand and price is in line with what seniors who live on their own would be willing to pay based on my conversations with local Real Estate Agents. 

It is important to consult with a real estate agent with knowledge of how panels affect your properties value.

Or working with a real estate agent yet? 

I think option one is better if you want build a lasting relationship with this agent.