My question is what ability we have to enforce certain “policies” such as requirement to maintain renter’s insurance(their leases don’t require it) prescribed method of payment (they currently deliver cash to the landlord’s local bank) or increasing their deposit (some are as low as $100, and one tenant has no deposit at all)?

Zero interest  2.

and subs should have no problem proving they have insurance and will add you to their policy this is standard Operating procedures. 

USAA and Amica do a great job of taking care of their policy holders and writing a proper scope of work / paying for quality work. 

It was about getting an insurance policy to protect you in case the bank calls a loan from the “due on sale” clause.

Their buying model wasn't accurate enough for their risk tolerances.

I have like ZERO bad debt, no car loans, no personal loans, like 3k in credit cards which I can pay off at any second, im insanely underleveraged on my investment real estate, have 820k in cash liquid, among other liquid assets like silver bullion, crypto, ect.

A LLC does add a layer of protection but there are other options as well such an umbrella insurance policy.

If its not on the MLS and the agent is marketing it outside of his brokerage (which it sounds like he is) then it is 100% a violation of Bright MLS's Clear Cooperation policy which requires all subscribers (i.e., listing agents) to post their listings on the MLS.  

Once you move out of this property to a new primary residence, then you could go with a Landlord policy like NREIG.