You can also check their reviews online at Google, Facebook, or Yelp.

Each town is a little different, some require you to do a landlord registration and/or will want to do an inspection before you put a tenant in (calling the town would probably be the easiest, or they may have the info right online).

You'll need good contact info for them to be able to collect, and ideally the new address for the tenant however which if you don't have can probably be found easily with some online sleuthing/ contacting their employer, skip tracing software, etc. 

The majority of buyers appreciate the expertise that a good agent provides (local market knowledge that can only be gained by being active in the market buying and selling all the time, looking at most of the new listings in person or at least online daily, a background in or at least understanding of building construction, relationships within the network of professionals in the industry doing deals, vendor referrals, legal protection through E&O insurance and keeping up with constant changes in approved contracts and required disclosures and forms, negotiating skills (the average person is terrible at negotiating directly and has no desire to, I find Americans are uniquely averse to negotiating and prefer to outsource it but I digress), etc.).

Look it up online and see how much u actually can buy.

A friend advised me to check reviews online and look for someone local with experience in single-family homes.

I wouldn't say you're going to learn as much going through an online course as you would an in-person one, but it is a lot more convenient. 

Then just yesterday, I come across the 1099 / 1099-NEC form requirements online from my own research.

welcome @Cam Caraher and congrats on joining BP, this place is the start for many, sure was for me longer ago than I care to admit.I'm not personally in your market, although was born in dorchester and grew up in NH, but this is a great place to meet locals.If you have not already a great starting point is the Meetups posted here, just search for your area and see if any meetups are happening. 

Recommended resources include books, podcasts, websites, forums, and online courses.