Do you think such a long-term tenant is an advantage or disadvantage?

The disadvantage is less return on your cash.

So 4 houses in 4 different cities- FL, GA, IND and STL.Id love to hear any suggestions or advantadges or disadvantages of having them in separate LLC's in each state or under one?

I have a much better perspective on financing my first out of state property and I see the advantage and disadvantages a cash purchase will give me.

One of the issues I've been pouring over forum posts to try to learn about are the advantages and disadvantages of cash purchases vs conventional financing for a buy and hold investor. 

While I don't see anything wrong with your plan, you don't have any sort of economic disadvantage and from what I recall, you just purchased a couple fourplexes at market with conventional financing in Vegas.

.- 7% ROIWhat are the ad/disadvantages of the closing?

There is overwhelming evidence that lack of money is a disadvantage and having money affords opportunity, yet people without money still claim money doesn't buy happiness.

It is negative when you look at the small picture, if you don't count appreciation/depreciation and tax shelter advantage/disadvantage, then you are simply fooling yourself, those two along with other factors will affect your overall investment.

If you have a free and clear property, you are more likely to be at a disadvantage if your ever sued.