Investor loans through Fannie Mae had skyrocketed since May when they decided to cap lender's investment percentage of loans produced.  4.1125% and 1.5 or so in points is not out of the realm of possibility. 

My initial goal is to have rentals that produce a combined $1500-$2000/month in cash flow after expenses.

In my market, if a tenant is working with a realtor, you are merely a rest stop in the house hunting game.Based on my regular review of listings, if you list with a realtor you are likely to have to absorb more vacancy than others.The 2nd is until recent market changes... now we all feel like pre-pandemic Brooklyn landlords- we could rent out a garbage can.I never saw the need.

You might want to get your regulars agent to take a look at it for your market.I'm sure agents fight to keep the deals together if things start to go south, like a tough inspection, or some other issue when the commission is more. 

I charge good rents, require steep security deposits, schedule regular inspections, take incoming and outgoing photos, videos, and descriptions, and hold the tenants responsible for every item.

Deals come in regularly.

Population density and low-income do not produce good results.Anway, I hope it works. 

The problems you describe are the exact thing I would expect to happen on a regular basis when trying to STR those types of properties.

If you had 100k in Canada and a job that produces 40k/yr, what would you do over the next 4 years in real-estate?

I have never heard of a person who works with a real estate investment company and is responsible for finding properties that are best suited for flipping.My first thought is why would they give someone else a deal if they are suppose to do it for the RE company but that being what it is, if they do this on a regular basis inwouldnthinknthey already have a fee system Why do you want to partner with them?