The LL is in the wrong, but you have been minimally harmed (some lost time and effort, maybe application fees).   

There is no harm to have your listing there too just set the limit for your stay.

We don’t know any PMCs to recommend in the area mentioned, but since selecting the wrong PMC is usually more harmful than selecting a bad tenant, you might want to read our series about “How to Screen a PMC Better than a Tenant”:https://www.biggerpockets.com/member-blogs/3094/91877-how-to-screen-a-pmc-better-than-a-tenant-part-1-services-and-processesWe recommend you get management contracts from several PMCs and compare the services they cover and, more importantly, what they each DO NOT cover.

I don't allow tenants to smoke any substance, or vape, inside their units, garages, or outbuildings.

In our culture, the idea of fast food and convenience is everywhere so what seems "easier" could actually be disguised to harm you healthwise.By just taking out some time in the day to plan and prepare for a healthier lifestyle will do wonders in the long run.

I’m grateful I didn’t, because I saw in the cancellation policy that they would close all credit they opened for you (which would harm your chances of upping your personal credit limit).

But if the conviction is remote in time (e.g. over 3 years ago) and didn't involve intentional property damage or bodily harm, perhaps the conviction is not sufficient cause. 

My insurance company won’t let me rent my 2 car garage or an office space that I have because it poses a “threat” of a non-tenant person coming onto the property and potentially posing harm to my residential tenants.

They already caused the harm by losing the 1st deal.

Giving your sister 250K of his equity and removing you from co-signing responsibility sounds great for you and your sister, but actually seems harmful financially to your nephew.