- Is it possible to avoid paying taxes if we just re-invest all the money to pay down the principal on the new mortgage (residential)?

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I am looking to cash out, so i would like to know if i should be adding more money into the rentals such as painting/roof upgrades?

In my experience, about 80% of them will break the lease early and you'll lose money because you negotiated a lower price!

It you think you can re-rent it in three months, then let her pay 4 or 5 months rent to buy out of it, with part of that being a credit for the security deposit money, assuming there are no damage deductions. 

Also, in a mainstream asset class like value-added multifamily, I see no reason to take a risk on a sponsor that doesn't have full real estate cycle experience or that lost anything more than a small amount of money (and prefer no money lost).

You do not need to have a ton of cash in fact you could buy a home with little to no money down.

I agree with @Brooklyn McCarty ...Too much money to get in and too many restrictions.

An example of this would be mixing your personal money and LLC money in the same bank account.3.

6 properties over 6 years is impressive.If you continue on this approach, you may be able to do better than 1 property per year if you make more money with your employer and are generating cash-flow from your renttal properties.Why switch strategies if you have something working for you?