I can be a minimalist so I have no fear of living through it.

As a newbie, I've read tons about the process from deal analysis to closing but getting over the fear factor was my biggest hurdle.

A Landlord can not rationalize your fears always but I would bring him an offer that you can’t be here if this isn’t addressed after “x” days/weeks.  

I have fears that STR is helping to add to the housing/rental bubble quite a bit.

@Brian Garlington the author called it "fear of missing out" but you could also call it a buying frenzy or even a bubble.

Biggest fear would be going through a life changing event like this (with a family), only to be devastated in a year-5years with a terrible decision.

To be honest, this is what I fear the most, getting sued by a tenant

Really, if you have no fear of qualifying, just make sure both lenders know that another loan is pending so that they can take the debt into account. 

My fear is that if I purchase a B/C grade asset and put money into it for value add, but can only find buyers willing to negotiate a cap rate that kills all my equity, I’ve basically wasted a lot of time, energy, and money just to break even or perhaps worse.

I fear if the offer is not strong enough and you have no leverage, you will be forced to take the deal that works regardless of where it is.