Justin,Strictly from the investment perspective of your question, if you can have your mortgage paid by tenants and get into the house with 3.5% down, you're leveraging your initial cash investment more effectively - you're controlling a $100k investment for a $3500 outlay vs. a $20k investment for the same upfront cost - and someone else is paying all or most of the ongoing expenses.But, this assumes all other things being equal.

Protecting your private lender's principle is of vital importance so make sure you have everything in place to cover them (low LTV, deed of trust or mortgage, promissory note, hazard insurance policy, personal guarantee).

Joint Tenants would mean each of you are equal 1/3 (provided your wife joins title).

I totally get your math and all else equal, you are making the best business decision - in the short term.

We plan to get an umbrella policy that will cover these new properties in an amount equal to the value of our current assets, does anyone have any guidelines or links to how best to handle this?

You merely have to trade equal or up in value.

If your description uses the center of a road, you can't locate that either as it may not be the center of the pavement.I've written meets and bounds descriptions for minor subdivisions but it takes a surveyor to locate property lines for improvements if set backs are questionable, don't try it yourself.Depends too on your lot, look at the plat, if the lots are equal sizes adjacent to you and you're in a subdivision your lot line will generally be half way between the homes, if they look similar.In some states a fence that has been erected for a certain period may establish the line, even if it is off.Don't go by utility boxes or telephone poles, but the developer may know if poles were set on lines, they could be.I've had legals that go from the POB westerly 196 feet to a "large oak tree" thence south to the center of the river, easterly along the center of the river 220 feet, thence northerly 246 feet to the POB (something like that).

I would tell her she needs to agree to pay a lease termination fee equal to one months rent of $1100 and you are doing her a favor as she is technically liable for the entire value of the lease.

The increased cost of using a HML as opposed to conventional is often discussed, but equally important is the shorter loan term.  

I usually offer 50% and share profits and losses equally (although I've been known to pay the investor back in full and take the loss on myself).