This is a unique home and it actually has a full kitchen, 2 bed and 1 bath downstairs and I think it might be well suited as a very large vacation rental(entire home) or both floors being rented separately at some point in time.  

Here are a few avenues folks often explore in times like this:You are already on this path - Owner Financing: It's great that the seller is willing to finance a portion of the deal.

Be aware that 5 levels of membership can create divisions within the ownership group because the same investment at any point in time can behave differently for each class of investor, so motivations may not be aligned. 

We rarely have issues, but it seems like such a small investment in time and money to take one day to verify. 

Additionally, I expect applicants to follow instructions in the advertisement and application, to make and keep appointments, to show up on time for appointments, dress and behave appropriately at appointments, and in general demonstrate throughout the process that they are someone that is easy and pleasant to do business with.

I'm not very intimate with the markets to the north and south, but I would start looking at price to rent ratios and decide what type of rental type and terms you want to invest in.

Needless to say, our first Landlord experience was not pleasant.

I if go back in time when I was a newbie and investor in Mexico and I'd need to get information about how two invest in Mexico, I'd want to hear from other investors who have done it before rather than from people who sell properties and that's exactly what the forums are for.

Suggest you check in with him/her on this additional service as your attorney is already intimately familiar with the file and you can often give them pre-authorized amounts to settle on vs trying to squeeze all the blood from that turnip. 

You also have to factor in time limitations.