Review their management agreement.

As long as they were closed on prior to Feb. 15th and can be proven utilized as rental properties via income and lease agreements the lender should not care how they were acquired.

If you are unsure about the investor paying you then yes write up some type of formal agreement.

I'm currently renting out one floor for $1,000 / month with an agreement to raise rent to $1,100 at the start of the year.

Then, if there is mutual agreement, together we could craft a strategy to invest in real estate that would meet our goals.2.

And then have them sign/fill out an estoppel agreement....

If you are not helping to qualify, you typically wouldn't be on title, so you'd have a separate legal joint venture agreement showing your interest in the property and the splits. 

Is there anything I should add to my lease agreement?

And yet, for the sake of the antisemitic bogeyman, all of these evil legislators and their base seemed to have come to this unspoken agreement that it's okay to throw EVERY SINGLE LANDLORD under the bus, for the sake of attacking this antisemitic bogeyman.

Or is this some future support that she anticipates a soon to be ex-husband is possibly going to have to pay her based on an informal agreement that the two of them came to between themselves?