I have been reading up a bit on how to creatively to this and I havetwo LLCs that operate in separate industries that I was hoping to leverageBelow is the plan I have1.

Again, best practice would be to form a separate LLC for rental from flipping business.

Would it be on separate things?

But like me when i have a subdivision that is in a separate LLC that LLC needs the developers license. plus the GC.  

I've been going through "The Multifamily Millionaire:  Volume 2" and in Chapter 13, they talk about property management ranging from 4-6%, on top of on site management that is on the owner's payroll, separate from property management, and that you should budget about 1 staff member for every 40 units.If you (the owner) are already paying a property management firm, why do you have to have on-site management separate from the PM? 

Separately, I have 50% ownership of an LLC that holds real estate on which we are building a new investment property. 

For a more accurate financial projection, factor in these additional expenses separately.

With the SDIRA you can have pre-tax or Roth but they're two separate IRA's.   

Any costs directly associated with building the basement apartment, such as separate entrances, kitchen installations, and bathroom fixtures, can be directly allocated to the rental portion. 

It's usually best to separate the attorney drafting the agreement from the title company closing the transaction if possible