Option D: you are considered a "disqualified person" to your IRA and as such are prohibited from engaging in any transaction in an IRA or receiving any benefits from the IRA (directly or indirectly), therefore I strongly suggest you avoid this option if you wish to stay out of trouble. 

If they get married it will help her earn SS benefits, etc etc. 

Being able to shuffle leads from MTR to MTR is a huge bonus and you can benefit from the economies of scale faster. 

Consider using an FHA loan to secure a 1–4 unit property with just 3.5% down and take advantage of tax benefits by living there for at least two years.

That's my biggest concern.But I should also look at the tax and long term benefits.

Quote from @Dean Sexton: There are benefits to both options.

And the real benefit of real estate that makes it worth the hassle is appreciation.

Phase I is: GROWTH.

I also do not take any money from my rentals as I’m in the growth phase with a W2 and low personal expenses. 

There are some benefits to having an LLC on reduced liability, but there are more expenses.