If you bought a TV that you use to watch the highly educational programs on HGTV - then it's a stretch, at best.I doubt that your $12k rental business needed $20k of some business-only equipment.If you bought something that is only partially used for business, like an iPhone or power tools - then you can only deduct the business portion (percentage) of such equipment.

Whats the fee percentage you pay the issuer for the 0% then? 

Upon selling the property she would make a percentage, which I'd like to know what you all think a good return on her investment would be, and I of course would pocket the remainder, turn around and re-invest in the next flip. 

I have software engineering background, so I guess that's bleeding through with my variable names.

If you have all of those finances stored in a single account that is clearly marked, the chance of commingling goes down because you are simplifying the task and removing variables that can cause error.

That definition would need to go into laborious detail as to what is included, what is excluded, and how to calculate each individual variable, otherwise it is easy to "game".

If your talking general residential there are too many variables to say when your specific property in your specific market during which local economic cycle will bear the best rental phase.

There are a lot of other variables such as building a energy efficient home (with solar),  home gardens, access to the internet, and cycling just to name a few.

Please note that the line of credit with Charles Schwab is likely a variable rate.

Early termination fees in contracts are not unusual and the ones I proposed are a small percentage of the remaining annual contract value.