Tell your PM that you don't like what they have and ask them to have the tenant remove it, simple.

Many of the tax planning service companies referenced herein want charge $5000-7000 for tax planning services which seems exorbitant for someone like me who is a single W2 earner with a pretty simple tax return.

This is simple math to figure out when they become destitute unless they change their cash flow.  

Simple... if you are moving more than 1-2 hours drive away from the property HIRE A PM!

As someone who started with very little help, I think your tech stack is one of the best things to focus on, to keep everything clean and simple.

This is simple, as there is no gain.

A generation using wayfair, ikea and on demand stuff has less and less interest in DIY events, certainly not at anything resembling a profitable rate. 

The more you customize the software, the harder it is to maintain and you end up with vendor lock which in simple terms you are at the mercy of your developer(s) as they are creating custom code that is difficult to maintain without them. 

Its not simple like you'd think. 

I've never met a DIY project I couldn't accomplish (yet).I'm not really sure where to begin, but I'm thinking about asking a more experienced flipper if they would be willing to let me shadow them on a project to learn the ropes.