Regardless of your decision, I would make sure you have a strong lease to enforce it, while ensuring your actions are aligned with local ordinances. 

Numbers not aligning was the deciding factor for them. 

If timing were right, sure... but the role would have put me as point of contact and sole responsible party for a 20% share of the ROI, and I would rather partner with an investor with 20 houses and manage them, and pay all the repair and wear and tear costs for them, in exchange for running them all at a 2k/door net gain... simple win win which would be income more aligned with the level of responsibility required. 

If those align for you then go that route.

Current 30-year rates are around 4.6%, you should be looking for sub2s that are close to that.Basically, you don't want to get yourself into a deal where the planets have to align perfectly for you to make any money.

If you have a true potential list of potential properties, I recommend aligning yourself with a few great Real Estate Agents who you are willing to develop a trustworthy relationship. 

That is, if your goals align with that train of thought.What are your goals for the future?

I feel like your perspective is very well aligned with mine.

If you, and preferably a premarital counselor, feel you're aligned and she is independently thinking of how she'll address the debt then the discussion can progress on you assisting her.

As far as interviewing a Lender, I would want to know more about how they operate, where their expertise lie, and does that align with my goals.