We have the opportunity to sell one of the properties for the full amount of the loan, but, since any attributed appreciation would be a short-term capital gains, are trying to best understand the implications and potential structuring options. 

since you can't predict what the market is going to do is there any other reason or attribute of the home that would make it worthwhile to hold on to? 

You’ll pay that, plus whatever was deferred from the 1031, attributable to that property.

@Tanner Connelly - One attribute I see of good lenders that distinguish themselves from not so good lenders is asking for everything up front and understanding what the underwriters truly need.

A Solo 401(k) can accept rollovers from most tax-deferred IRA plans and any tax-deferred or Roth employer plan such as a prior employer 401(k).As an employer sponsored retirement plan, a Solo 401(k) has several advantages over an Individual Retirement Account (IRA), such as higher contribution limits, the ability to house both tax-deferred and Roth funds within the same plan, a participant loan feature, and an exemption from tax on the portion of income attributed to debt-financing in real estate investments (UDFI).  

That information is that you can include more than just a roof in the financing and that as long as it could be attributed to the solar installation, it would be covered. 

@Kelly LaneWhen an IRA (or other tax-exempt entity) uses leverage like a mortgage, it creates taxable Unrelated Debt-Financed Income (UDFI) which is then paid as UBIT (Unrelated Business Income Tax).The percentage of the income directly attributed to the IRA's down payment is not taxed. 

I have a harder time in situations where let's say a property A has 4 bathrooms, 4 bedrooms and 1800sf and no garage and 1 story, while renovated on the same street property B has 3 bedrooms, 2 bathrooms but 2200sf, garage and 2 stories.What are the priority metrics in this case when every attribute seem to be different, but it's the only type of comps available in the area to lean on?

@Blake Ramsey evaluating markets is the right approach, but i believe it’s less about the numbers but the attributes.

I attribute a lot of our success to our great working relationship.