To which Id say it depends on when you bought, how you bought, what you did to the properties CapX wise, and how you managed.

We just need to make sure the lender can do the loan without the tax map key   really depends on the lender, a direct lender who uses their own money may come down but a hard money company with 20% down on land even with other collateral may not want the deal.

For many years I was contacted by the housing office to provide input of my rents, both Section 8 and market rented units and participated in their annual surveys. 

Big things is be realistic on timing and maybe provide a mover and or storage unit deposit as they may not be able to figure that part out on their own.

But perhaps you would be better served helping a local experienced investor find deals and ask them to show you exactly how they analyze deals, what's good vs bad, how do they finance (debt vs equity) etc etc and understand their business model that has a proven track record by providing value to them.

I would look FAR AND WIDE for someone to do an investment property HELOC -OR- go to a bunch of banks and CUs (including who you bank with now) to find someone to provide an unsecured (or secured if you have other collateral) LOC to get rid of the high int debt.

All of this really depends on your goals and timeline though too.

I can see how starting with a 4-plex could provide better returns and learning opportunities without an overwhelming jump in complexity.

It depends what your goal is.

The choice between JVs and syndication depends on personal aims and interests.