They can also go back farther in time, and do an appreciation factor. 

Will depend on several factors like the type of property, type of tenants, your risk tolerance, other assets you own, your estate planning, laws where the property is located, etc.Any lawsuits would 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).

I've found that when looking at properties quickly it's safer to assume 60% of rent will be expenses (prior to factoring in mortgage payment -principal and interest-).

Here the more bedrooms the better so if you can fit 3 that’s great but the city or county you’re in may limit you to 2 depending on size allowed plus if you’re on city water and sewer vs septic that may play a factor as well because they may require a separate septic system which is $$$.

Some factors are the tech, education and healthcare industry.

It depends on a lot of different factors and is a pretty personal answer:Income.

Most investors focus only on rates and points, but there are a number of other factors I would consider more important than paying 1 point less or 1% less on an interest rate.

The additional costs not factored include: adding electricity to the additional 5 units, paving the driveways (would use either limestone or asphalt), and then the biggest expense and unknown would be bringing in the additional mobile homes.

-likely but without my handy crystal ball, the timing of that will depend on not real estate but other factors.  

Those vacancy can depend on several factors:- Are those rental priced competitively?