He helped me out, made an offer & we had it locked up in 2 days, closed in 3 weeks.

The key is finding out what the seller wants as far as terms but the majority just want a quick close with the highest price. 

I am closing on my 1st rental (Duplex) next week & I am going to self-manage the property.

Primarily self limiting beliefs.One of my clients just closed on their first commercial deal and they only had one duplex before I started working with them. 

.$80k cannot get you at $400k house, you need closing costs + reserves.

It was a gut punch to see the tenants whose income we were counting on mass exodus the building right after we closed Did you work with any real estate professionals (agents, lenders, etc.) that you'd recommend to others?

I say watch this space as the net must be closing soon.

Also do not take documents off the internet, get an attorney to draft documents for you and also always close with a title company. 

Buy something close to parks, nature, trails, or outdoor venues.

Your example (and calling me a bit of an ignoramus) isn't even close.