B or better neighborhood with an active sales market. 

I also actively invest in real estate.

(completely passive, some activity, very active). 

I can filter out things like active/pending MLS or recently sold properties.

To illustrate this there are probably 50+  active MLS properties in North Philadelphia/South West Philadelphia and other lower tier neighborhoods at any given time where you can complete the BRRRR  method but the real estate is lousy.

I've added him as an account manager in the account so that he can see the activity.

I'd shy away from actively openly sharing the intention to do it beforehand. 

HOA and insurance costs as low as possible.Can you suggest a few good cities in the FL with lower vacancy rates and close to nature/activities?

I'm going to keep track of my real estate activities in management of an STR, and will track the activities using an activity log.

Our track record of over 36% IRR to our investors is hard to match in this industry or any other (and that includes two recessions, unlike most of the currently active syndicators in our space).