If there are no passive investors this is technically not syndication, correct?

Tax laws for Dummies, keep it simple lol At 20+ properties, you have a CPA I assume, and these questions are really for him.Shortest possible answer, with technical terms in parenthesis:1.

Technically, could I accelerate the loan?

Im sure there is some loophole or technicality that perhaps you are unaware of.

You do not technically have to take out a new loan if you can replace that with cash from any source.

The only two funds (even if not technically notes) are Fundrise and AHP. 

Could the problem be circumvented, in the short term at least, by the way in which the "2nd unit" was rented - by stipulating 2nd floor rather than all the rooms in the legal 2nd apartment, which is both 2nd and 3rd floor (I would be living on the 3rd floor which would technically be part of the 2nd apartment)?

The 5 days of staffing at the facility is what the current owner does. 

Although I guess you can't technically do that because the 3.5 is only for FHA and you can only have one at a time, correct? 

While technically you can do so with 48 hours notice, it sounds like one or both units are being difficult so I don't know what you're going to gain from it.