This means that you will probably need to pay registration and filing fees in at least 2 states if you don’t buy CA property as a CA resident.Any lawsuits should be limited to the assets of the LLC and not your personal assets (assuming you run the LLC appropriately and the corporate veil is not pierced, some debate as to SMLLC).

If you’ve owned it less than a year you owe regular income tax on it plus any depreciation recapture.

Right now, I'm mostly a stay at home dad, but my dream is to start looking into that more seriously once my young kids are all school age in about 3 years, something that I can do to earn my family some additional income while maintaining flexibility to take care of the kids outside of school.

(Fannie-Freddie just started allowing projected income from ADUs to be counted toward qualification this year.)Just in general, though, any kind of rent appraisal I see here in Colorado -- be it for short-term rentals/Airbnb or for LTR -- are woefully low. 

Is the $1500 income the rent or the cash flow after properly allocating for expenses?

Trace the filings of the corporation you discovered— might give you some clues.  

I just want to make sure I understand correctly, so even though she will be receiving a lump sum in 3 years from the balloon payment (it is an investment property she's selling me, not primary residence), she can't 1031 that because technically when she sold it to me today she became the bank and no longer owns the property, so basically the lump sum paid to her at the end, is the same as a bank making money and therefore taxed as income tax?

Code § 7701 - Definitions, my understanding is that the answer is NO, but maybe I am wrong.As the actual rate of withholding is 15% of the sales price, and as the refund (if any) would be "within 90 days", it can be a major setback for my company´s flipping cash-flow because 15% is way higher than the taxable income (and of course than the tax itself), so we would be in the necessity of capital injections to flip the next properties.If any of you have comments on this, it would be very helpful.Thanks in advance

Then as a married couple they can write off their losses against their W-2 income. 

You likely won't be able to take any deductions on your personal income, but real estate does have tax benefits.