This landlord already knew before i signed that sometimes my brother and i don't always see eye to eye.

Use the remaining tax free money from your sale and invest locally with it so that you can keep an eye on what is happening in your market. 

The tenant finally paid the rent via an online credit card payment to catch up. 

I found a pretty solid realtor but anything else I should keep an eye out for as I dive into this ?  

I am getting coc's of 15 % on preliminary analysis on rental calculator after putting in CAP of 10%. is there a catch ??

If you catch it early, it can be minor. 

You're thinking long term, which is great, but that means all the long term CapEx items are going to catch up with you...one more reason to limit your time with SFR and aggressively move to MFR where you can realize efficiencies of scale. $150-200/unit/month is probably more attainable.

By training under the watchful eye of someone smarter or more experienced, we can only get smarter.

@Grant Sevek, I don't keep a super close eye on HELOCs, but usually a few points above a 30-year mortgage; often variable rate; 75-80% total LTV on investment properties.

VRBO and Airbnb platforms make it pretty easy to self manage.Find a great cleaning company that can handle turnovers and be your eyes and ears and a handyman for small repairs and you are pretty much there.You can use sites like TAKL.com to find other services that you don't routinely need.