I just turned 60 and would like to retire on REI passive income by age 70.

DSCR loans primarily evaluate the property's income-generating potential rather than relying solely on your personal income verification. 

What numbers should I be looking for (is grossing $100-200 a month once a long-term rental too risky/not beneficial)?

These loan programs take your good credit, the property value, and the property income into consideration for what size loan you can get.As for your rehab loan, I think that sounds like it is pretty in-line with what I see for the two dozen programs we utilize. 10.5% to 12% with interest on drawn funds only is where I try to peg most client deals.

Most investors goals are more modest perhaps to replace their W2 income and get financial freedom and that doesn't require 100 doors.

I have accumulated paper losses (e.g. depreciation) I’d like to use to offset my spouses W2 income.

I like the freedom of doing real estate deals, while helping people get what they want out of their opportunities to have property as another income stream.

its incremental depending on your renters our area is more concred with leed 140 compliance in buildings so i dont buy anything older than 1985 without a budget to convert the property. currently we have 100% occupancy in a high income area so having these amenities is critial for new buildings without enough Power for in Garage Car charging people with jobs and new Teslas wont rent. https://www.globest.com/2021/0... 

so, what I want to do is to create passive income with cash flowing properties.

Many STR owners have ventured into MTR to supplement their income and we have far more supply than we did 2 years ago.With your desired price range of under $100k inventory is likely to be very limited.