In 2025 does it make sense to build a 4plex and house hack it or is it better to buy existing multi-family? 

I would look into any regulations that might require you to have a fence around the pool as well :)Hope that helps.

I don't see similar features in existing cabins and my gut tells me that it might be nice draw when weather transitions from summer to colder temps. 

"I have a very simple criteria for when an area is gentrifying as opposed to just generally improving: If it makes economic sense to buy (at market price) and tear down an existing structure in order to build and immediately sell a new building, then the area is gentrifying.

There are actually THREE kinds of subject to transactions1- subject to existing mortgage without lender approval2- subject to existing mortgage WITH lender approval3- subject to existing mortgage as part of a seller financed wrap around mortgage.with #1 and #3 it’s in everyone’s interest to utilize a third party servicer, who collects and then distributes payments.  

Keep in mind all this stuff is uber regulated, very detailed, far from simple.

This is virtually non-existent with SFH's but is commonplace with 2+ units.

Make sure any renovations comply with local regulations and obtain the necessary permits if plumbing changes are involved.

Can regulations change?

What types of organizations are you working with in your master lease agreement for your existing properties?