My lease also says I am authorized to show it to potential buyers or renters with proper notice.Some tenants fight this and I typically let it go because I know they'll sabotage any showings anyway.

New tenants are not authorized unless they go through me with an application.

You don't want to niggle over every last detail with excessive back and forth negotiating.

My coworker has done excessive research on this and had the network established (local agent, appraisal, property manager).

On the web, it seems like Sue Cruddas and Grifaldo Properties have decent reviews. 

I would have had the seller sign a 3rd party authorization and limited power of attorney when we closed on the sale.

BetseyWe have listed our properties on Google Business .Since doing that, we are running about 50/50 of people coming directly to our web site and going through HomeAway ,VRBO or Trip Advisor or Flip KeyOur Season is almost 85% word of mouth. which really helps cut down booking fees.We have seen and been told that during season once guest find a place they book for the following year because if they don't they won't be able to get in.We have been doing this going on 3 seasons now, when we bought the place we inherited a couple of guest that have been staying on the property.

Will all partners have full authority? 

I feel like this is fair bc it is when their lease ends, and I'm not responsible for giving them any extra time while they were trying to sort things out with their roommates to sign a new lease with me.Honestly, at this point, I'd rather have them out of my property as they've been difficult to deal with during this process and other items have popped up in the past (e.g. they've clogged our kitchen sink by pouring excessive oil down the drain, broke the garage door within a year of their first lease, etc.)My questions are:-What happens if only 2 of the tenants vacate when the lease ends and stay for an extra week?

It's called the Federal HOUSING Authority, not Federal INVESTMENT Authority.