So to use a very simple math example: if a full year's depreciation (house value, closing cost, less land, etc. / 27.5) is $365 then 4 days of ownership would allow me $4 of depreciation or do i use the full $365?

Not too hard but you’ll probably have to pick up the phone.

I just picked up a property for 100K and wanted to rent in Hemet but HOA put a stop to that real quick and we just flipped it for 170K.

Partnership taxation can be very simple but can also get very complicated very fast, especially when you get into substantial economic effect issues.

My LLC is registered via a 3rd party and my name is not anywhere on the articles of incorporation (as I am trying to keep some privacy but also have that wall between tenants).With this being said, after you transfer your LLCs from your personal name to an LLC, I understand you cannot change the terms of the existing tenants lease, however, is there some sort of short and simple communication I can give the tenants letting them know that the home has transferred ownership and that their lease agreement held up and house under XYZ LLC? 

A regular IRA at Fidelity or Schwab is just simple - put your money in, choose your fund, and forget about it.To your "in case they decide to do real estate later" question.

In summary, I don't think you pick between a Mortgage or Promissory note, and the Promissory note allows you to avoid mortgage lending guidelines. 

Now I was looking through some of my hand picked properties yesterday, and saw a beautiful 1920's colonial that needs professional restoration, at a great price, where I think a flip is the best way to go.

This is all we have.Am I missing something more simple and obvious? 

Indianapolis & Philadelphia have properties ripe for the picking right now for rentals, and appreciation in those areas may be substantial in the near future.Good luck