UBTI is generated when a tax-exempt entity engages in a trade or business on a regular or repeated basis - such as flipping properties.A Solo 401(k) does have a narrow exemption from UBIT stemming from Unrelated Debt-Financed Income. 

I have been doing a Roth IRA for about 4 years and I opened a regular brokerage account as well.  

Aside from the regular MLS such as Realtor.com, here are some options:HomePath.com for REO listings, Auction.com (properties listed there are sometimes eligible for conventional financing), Xome Auctions, LoopNet (perhaps not the greatest resource but look anyway), Hubzu although it can be (tedious and confusing), also check your city or county website for auction properties ( a very few may be eligible for conventional financing), HUD Homestore (another tedious process but worth checking)ForSaleByOwner.com (search your area, not all properties listed are on the MLS)4SaleByOwner.com (ditto)Craigslist Toledo OH, real estate for sale by owner listings (beware scams, but sometimes good things show up)Facebook Marketplace for Toledo Ohio, there is a real estate sectionLocal bulletin boards- post a free ad saying what you are looking forBigger Pockets Marketplace!

A few of us used to meet regularly but we havent in a while.

I think your ARV is comparing this to regular SFR’s outside the park.

You can buy it at Menards and other similar stores.  

We work with out of state investors regularly - it can be done!

I kind of assumed that the title company could set up the 2nd mortgage with the monthly payments and calculate the principal/interest for a fee of course but when I called my regular title company they made it seem like I was talking a foreign language.Who handles the administration of your owner financed deals??

The buildings are in an excellent location on a main 4 lane street right behind a large grocery store in a nicer part of town.What are your thoughts/concerns on the finances and price?

I firmly believe househacking is one of the best ways to get started in real estate and we help people househack in MA pretty regularly these days.