If its not being reported to the bureaus then the only thing you have to concern yourself with is (As Jay points out) any potential deficiency you may be on the hook for. the actual physical processing of a DIL is very similar to a foreclosure in that there is title work, recording of documents, etc.

Should I be concerned that the husband has no credit history (I'm wondering if this is indicative of past financial hardship/bankruptcy)? 

And eXp offers health care... and you can do business in any market throughout the US and in 27 countries while collaborating with and gaining support from over 90,000 agents Worldwide... 

This thorough investigation helps identify potential red flags and ensures that the sponsor has the resources and expertise to execute the project successfully.Financial AnalysisExamine the sponsor's financial statements, funding sources, and capital structure to evaluate their financial health and stability.

My concern is that my DTI may be negatively effected if I refi my primary 1st.

My main concern is seeing that a lot of clients are using cosigners and coborrowers to qualify for houses and are having trouble qualifying based on their own incomes.

It seems that those areas are full with new inventory. my concern is that is too close to the Mexican border and that there are many lands available for new construction.

OP was concerned about having his money being spent on a dream vacation.

My biggest concern is finding the right contractors.

I have concerns about appraisals coming in where I'd like them.