Am I prepared to hold properties longer if market conditions change or if a flip doesn’t sell as quickly as anticipated?

so those owners are pretty comfortable - no mortgage payment - and they don't need to sell, and they don't care where an investor "needs" the price to be to make money. 

BUT, I am sick living in construction and would like to move to a new home and then finish fliping and sell or hold the two homes asap.

Your goal is to secure this payment at the 18th month mark, by either selling the note to an private investor who's interested in a guaranteed 5% or you're going to refinance and pay the note off completely. 

Quote from @Meliisa Lee: I recommend splitting the properties or selling them off and splitting the proceeds.

With that being said, do yourself a favor and do the research yourself on zoning, valuation and ACTUAL rent before talking to STR specialists who make a living on selling these =) Just my 2 cents...

You haven't provided us with any information that would help us help you.My recommendation: do not sell a property unless you have a plan to invest it in another property that will perform better, or if selling will move you closer to your goals.If you don't have a firm plan, hold onto it until you do.

As a broker, I "buy" a mortgage at a discount from a direct wholesale lender, then mark it up and "sell" it to my client to make a profit.

I recognize that when my family visits I'm hurting my profitability, but that would be once or twice a year and its part of the selling point to my wife to purchase a property.Where I need help is running the numbers. 

After two years, they can sell the property to you as your first solo investment.