@Jessica HuynhI think @Zack Karp or @Michael Facchini would be better able to advise on this but I'm guessing that you're unable to get pre approved on your own as the sole borrower, correct?

Am I legally allowed to ask for the entire seven months rent to be pre-paid in a lump sum?

The cost of construction is pretty high at the moment for sure, I guess there's a lot more value to be found in building something pre-existing.Building this unit would add a chuck of value to the property but probably not quite $300k's worth I imagine.

I want to help them get pre approved but don’t know where to start.

It is almost a requirement in this market to offer a high DD, so it’s important that you know the status of your ability to close a loan - get pre-approved not just pre-qualified.  

Start an eviction process as soon as the tenant default, best case scenario you work out a deal and drop the case, worst case you move forward with the eviction and you didn't lose precious time trying to make things work (guessing you're in a C-D areas of Detroit, tenants are well aware of the process and like to play the watch to stay in the house for free as long as possible), navigating the courts since covid is a lengthy process so the sooner you start the better. 

The big question is it worth it to get into the 12 unit building for the long term play of holding for retirement passive income or not pursue it and and try something else that may or may not work out.

The Traditional SDIRA would be transferred to the Solo 401k as pre-tax money and if the Solo 401k allows for it, an in-plan Roth conversion can be done.

I’m trying to pre-calculate and figure out what I would owe taxes on.

I am currently being pre-approved for a first time home buyers mortgage (not sure on fixed or not), and I imagine I would need roommates for income cushion if I move into a place.