Would the same investment be better in a Solo 401k if that meant it was not subject to UDFI?

This is a deposit, not a fee, and is meant to stop shoppers.

Does anyone know of a good community that's specifically meant for people who are more advanced in real estate? 

This affords you 2-3 properties using a portion of the $400K you have and the rest to hold onto for reserves and to stay cash fluid.

Meant to quote ya!

However, when my agent said this basement was piered which meant the walls are "caving in," I called the listing agent and asked.

...this is not meant as an all-inclusive list, just a general starting point.

Relationships are meant to help eachother out and trust. 100k is a chunk of money, so what I would do is find local REI and fund their deals.

Here is a link that describes that issue in part. https://www.rocketmortgage.com/learn/fha-identity-of-interes...If this is meant to be your primary residence, why not deed the lot over to into your name and do everything in your own name?

If you decide to go the mortgage/cash split it keep you cash fluid and puts you in a better position to have cash on hand for assets and reserves.