I'd start small and think about the least time-consuming and the lowest-risk strategies considering your busy work schedule/ lack of bandwidth to take on an additional job which is basically what real estate investing needs to be in order to be successful. 

I'm honestly surprised, right now our only debt payment is a 857 mortgage, no car payment no student loans no credit card debt, and good credit 740's. she doesn't make just a lot (41k a year) but with the 857 mortage payment, her debt to income shouldn't be much over 25%.

I know a guy who bought his primary residence there with a credit card!

Local credit unions, big 5 banks, regional, everything in between.

Most Lenders will require a minimum credit score of 620 or higher to qualify4.

What documents do they require, what credit scores do they allow, how do they verify previous rental history, etc.?

Can someone explain why payment with money order would be better than reporting payments to credit bureaus through RentRedi?

I can't imagine it making sense down the line once I have say 20 properties and 20 LLC's, to have a stack of 20 credit cards that I'm juggling.

An example would be credit score, if that is what makes your trust someone that is completely fine.  

Go borrow on a line of credit or get a friend to lend you some money to catch it up.