Fannie/Freddie guidelines for house hacking

[Logan Fast]

I found a 3-plex that I would like to house hack. The plan is to use an owner occupied 5% down conventional loan. The seller is willing to carry a note for the 5% and accept monthly payments until it’s paid off. This would allow me to get into the house for almost nothing out of pocket if it works, but I am wondering if Fannie/Freddie guidelines disallow something like this. I did ask my lender but I know there’s a lot of experience on this site so I wanted to post it here as well.