Since you want to aggressively invest in the near future, you will need cash and the 30 year option is the right one for you.

Can I find 15% down payment options do you think? 

hey David,As a broker, I have several options if you're looking to only touch the equity in a second position lien on investment property. 

If you have equity and decent credit, a conventional Fannie Mae HomeStyle (or the Freddie Mac version) would likely be the better option instead of an FHA 203k loan (which will require a 3rd party HUD consultant to oversee the deal in addition to having the contractor involved). 

I am a land lord but don’t own my residence.What are my options?

Try to get an extended closing and/or options to extend the closing until you are ready to close on the sale of your relinquished property. 

I’m not sure what is the best option here, if anyone could shed some wisdom that would be immensely appreciated. 

I know there are a lot of options, especially since they are family and willing to carry the loan. 

Your suggestion to list on open market likely is the best option for the OP.  

.), so I'm seeing what other options there may be.