I also have a lending partner who can finance STR deals with only 15% down if you wanted to preserve some capital.

Wonder what they charge developers to access their capital resources.   

Great tools that get updated regularly.I am on the lending side of things and would be happy to hop on a call with you anytime to discuss financial strategies and help answer any questions you may have about nearly any loan product available to help you on your journey, even if they are not products my capital partners offer.We are all here to help you learn and grow.

I also have some capital to contribute.Could someone explain how syndications are typically structured, and how are people using Other People's Money (OPM) to build large portfolios with little to no money down?

I do agree raising outside capital can help with scaling.

Long term goals in mind that I need a track record and capital for! 

Should We:Sell, take advantage of the capital gains law, move, and pay the mortgage off on the new house, credit cards, etc…?

US, UK, Australia and other parts of the world are more for "traditional" investing in real estate for capital gain.

They also didn't get hit with capital gains on the entire purchase price, which enables them to keep more of their money. 

I have a private investor who will lend his own capital for ADU financing.