Only two of the three cabins were rented out - I converted the third cabin to a rental as well.

Management of vacancy and maintenance are the two largest costs of 3rd party management. 

I had a third owner (tax lien investor but had purchased the parcel years ago) with Warranty Deed recorded just transfer the deed and  give me the property because he didn't want to deal with sending certified checks to the county for taxes every year. 

If you acquire a third, your 1st LLC does the same thing: forms, capitalizes, and owns the third LLC to own your second rental.

Second, a "gift letter" stating that both parties acknowledge the full amount in question is, in fact, a gift that need not be repaid for any reason will tend to help mitigate some pestering from underwriting.Best of luck!

Consensus builder; highly adept at constructing transactions that benefit all parties.

You can also ask the seller of your target replacement property to accept the note as part of the consideration/payment for your replacement property, but most sellers will not touch a third-party note. 

The current lease is month by month for either party (30 days notice).  

We might possibly purchase a third rental.

Regulation and compliance varies by state, local jurisdiction, transaction, parties, terms and a couple others.