Additionally, it's easy for a house on one lease to get absolutely trashed by the renter.

Great credit.

Is there a way I can "co-sign" with one of my parent's credit cards and be on their credit history in order to boost my credit score? 

Do you mostly rely on your property management software, or do you have additional processes in place to keep things running smoothly?

It may be worth letting them know about the prequalification requirements (credit score over xxx, salary above xx,ooo/year, etc.) in advance to weed people out.

As a backup plan, if I have to go with a local PM company that only leases the entire home, could I use an addendum to add additional tenants to the existing lease while ensuring everything is legally structured?

Additionally, the contract with the wholesaler is set to expire on Monday the 27th.

You pay your agent at closing (think of it as an additional closing cost) Depending of the situation and of these options can be used by you and your agent to negotiate with the seller.

The teacher was an actual financial educator but they repeated themselves a lot and were telling the students to go in and apply for credit cards DURING the course to purchase the next course for $15,000!

I track the principal as a Liability account in Xero, and whenever I add it to a report, it always shows the current balance, rather than the change over the chosen time period (like with expense accounts).