There's also plenty of existing assistance out there, from 3.5% FHA homebuyer programs to Section 8 to SSI/VA disability, etc. 

I hired my own expert and discovered these issues did not exist but that the expert the 3 buyers had brought in wanted to be hired to do the work so they blew them out of proportion.

I would anticipate a semi-guaranteed government run insurance program, similar to the national flood insurance program of some sort and perhaps connected to an existing department of housing program to manifest.

I’ve been offering a $100 referral fee for existing tenants who refer a new tenant to any of my properties.

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

We were in a financial position where we could keep our existing home, upgrade, and purchase another home.

If the structure on the property is determined to have no value, be careful when you consider paying the “value of the land”.The value of raw land is different than the value of land with an existing structure, even if the structure has no value.  

Can you give the forum a few numbers on your existing properties, including estimated values, current loan balances, current rent on the duplex and expected rent on the SFH?

Look up ideal existing performing properties, your "hero's" as it were, find out who own's it, and reach out to them. 

Being new I would suggest started with existing builds but building small multifamily in a small town with a rental shortage could be a smart move (someone's gotta do it).