Many property management companies have high turnover and are frequently looking to take on new hires in roles that do not require you to be licensed in the state of Minnesota.

You could turn the matter over to a collection company (including law firms that do collections on contingency), but normally, they charge a very high percentage of what they recover, and you normally have to authorize them to settle for any amount the want to.

I don't know my buying power yet but I already have one house that's been rented out for a few years now. 

You can get high night rates during football season and holidays, but outside of that they drop rates below $100/night to minimize vacancies.

Although I do not have a house that would benefit from one of these compact units, we have replaced 3 out of 4 of our homes with the LG 5 cu. ft High efficiency top load no agitator washers & the 7.3 cu ft top load dryer and my cleaners absolutely love them for the large load capacity and the custom drying time ability. 

I have good personal credit (~730-740), average-high personal debt (mortgage, student loans, vehicles,) and I am employed making $90k/year.

The rate will be high though. 

However, with mortgage rates being so high when I bought, I am worried I will have some negative cash flow (approximately 200-300 per month as a long term).

A heloc is an open end mortgage or in simple terms its a high risk credit line similar to a credit card that sits in 2nd lien position adding another trade line to your credit and reducing DTI.Just like a credit card if you ever miss a payment on any debts on credit or if your scores drop unexpectedly they bank can close or reduce your line of credit.

Unfortunately you are going to get different answers from different people, especially from Realtors trying to solicit business in their market.What I have been noticing is that even in landlord friendly markets, prices are high.