(Not to say there is not a business model, even a lucrative one, that does not care who the client is but just cares if the rent will be paid.)  

We have rentals but wanted to try the fix and flip model to see if we enjoyed it and we did!

If your looking to go bigger, I would look into a syndication model. 

FWIW I've bought all those guys stuff, they all are slightly different and all are very good IMHO.See my business model:  go to my profile, first parapraph, read the file:  Bullet Proof Rental portfolio.Best of luck. 

I would also like to follow a similar model as yours - OOS, build a team, research and pull the trigger. 

We have owned gas stations so of course this information is familiar with me and the business model.  

To me at least, that seems like a much better first filter than any "rule" If it passes that sniff test then you make an offer at your price and model to your hearts content.

Investment Info:

Small multi-family (2-4 units) other investment.

Purchase price: $74,000

Cash invested: $74,000

What would be a good model for variable income on "properties managed"?

So, you are certainly right, there is a lot to consider and you want the investment vehicle match your financial model (you also want this outside your IRA) but I'd rather deal with that than just letting Wallstreet determine my retirement!