I want to build a private lender’s list to help with rehabs that I want to do exclusively. 

And I have an AMAZING lender that I work with exclusively.

We had our own strict limitations on who could rent our place that precluded large groups, and we rented almost exclusively to families.

I believe the DC area is #2 among cities with adult roommates next to San Fran so this may not apply to a lot of people.

Finally, I spent two years almost exclusively working with investors, providing nearly every type of financing.My guess would be this: there is a very definable trade-off between local knowledge and access to properties that "check all of the boxes". 

Four adult joint tenants.

You can balance the two ideas as they aren't mutually exclusive.

I'm looking at a property now that has been mis-managed by some adult siblings, who received the building after their parents' death several years ago.

House recently went from exclusive bidding period to extended, and I'm quite positive it will sit there untouched, until at least one price reduction (and probably past that).

How much property value can I buy using 1031 exchange, after taking $500k out for 121 exclusion?