Also, I’m not sure where you’re located or how big the house is, but a couple years ago we replaced all the windows and put new vinyl siding on our primary home (“basic”1200 sq ft ranch) for around $13k.

Ongoing cash flow need not be your primary focus for the dollars you've already saved.

Our Financing Contingency ended 5/6, so now we are out a $5k Earnest Money deposit (plus the appraisal, survey and inspection, $7500 total) and don't get this great deal unless we act fast.In short, we provided to income docs for my wife, but our current primary residence is in her name, so that didn't help the DTI much, and we ended up losing the deal. 

Not people who purchased it as their primary residence and then rented it out once they moved away.

However, I think the only difference will be if you are renting a room out of your primary residence.

 I haven’t purchased an investment property yet (outside of my primary residence kind of being a live in flip).

My current primary residence was a foreclosure.

I'm not a fan of the platform, but I've found some great leads for more-rural properties on Facebook Marketplace, of all places.I've never seriously pursued any, though, since I like working near where I live (time=$). 

If they have experience doing this would be my primary concern. 

The husband has very good credit of 706, no late payments and is the primary breadwinner; his wife is a SAHM, has poor credit of 594, mostly due to late payments (some 120 days late) of student loans, some as recently as April 2018.