I know I wouldn't want my kids or my parents living with me, but I don't want anyone living with me outside of my wife and my dog 😜

No pets. 

With an HOA fee of $275mnth thrown on top, which is ROI for that as we get everything exterior covered 100% including lawn, snow, private dog park, hazard insurance, private playground etc.. 

Their security deposit is $1,400 and they paid a $300 non-refundable pet fee."

I've only ever had one person leave owing any money, and that was due to dog damage.

Zero dog in the fight but I know they have very experienced people running their self storage division and are buying themselves to my knowledge.

The yard is not secure, and may not be used as an enclosure for pets.  

Also, ensure that they are in compliance with lease terms, i.e. if they have pets, is this allowed?

We also have a "no pet" policy were a couple tenants brought in pets that caused issues. 

Former Realtor here, so no dog in this particular hunt.