The new design takes the home from a 3 bed, 2 bath to a 4 bed, 3 bath, 2,400 sq ft rambler on a large lot in highly desired area.

Account holders can't take any write-offs personally for investments made in the 401k.

Ask your employer if you can have your pay split up into three deposits, one to investments savings, one to your checking account for personal use on a daily basis, and one to an emergency account you can tap into so you don't have to tap into your investment savings.

I have found ChatGPT to be particularly useful for testing new Book Covers for BiggerPockets, such as our foray into the personal fitness category with upcoming title "Sweat for Life": 

This deal proved to be the perfect balance of financial gain and personal enjoyment.

Just my personal opinion - get a mentor or a person who already has good experience running STR business, preferably in your area (but not 100% required). 

This is so I know if I should keep the person I currently have.

Just be mindful that you can't 1031 a personal residence but it might be eligible for capital gain exclusion from section 121.

For instance, do 2/2 properties typically have longer average stays, or are they more desirable?

One-person rental units are in the highest demand, and co-living directly appeals to this market.