Especially with a long-term hold approach.

Don't go for the highest number of doors, go for what will get you the most in the long run. 

We lived in it for a year, remodeled both units and put in place a long-term tenant on one unit and a mid-term tenant on the other.Here's a little more details about this deal:*   Purchase price: $163k*   Financed price: $132k @ 7.625% APR*   After repair (estimated value): $225k*   Gross rents: $2150 ($750 one year lease & $1400 six month lease)*  Annual taxes and insurance: $7000*  Approx credit score: 650 (I used interest free credit card to pay for remodeling this property and maxing it out caused my score drop almost 50 pts!) 

I renegotiated a Lease with my first property a few months back and pretty much stuck to the same terms as the prior lease agreement (minus rent increases). 

Does it have to be a specific reason to allow them to break the agreed rental contract or it only applies to long term lease? 

(Both legally zoned)  My current inexperienced understanding is that you can NOT be prevented from adding or replacing trailers so long as the pads themselves have been grandfathered in and are legally zoned.

Thus, I understand your objective on Bigger Pockets is not to learn more about REI or to help others on BP. 

They are often classified as operating expenses or maintenance expenses rather than capital improvements (assets).Washer/Dryer/Stove/Refrigerator: These are assets as they are considered durable goods that will benefit the property over an extended period.New Baseboards/Trim, Doors: These are generally considered assets because they enhance the property's value and are not typically replaced frequently.Furnace/AC: These are significant components of the property and are categorized as assets due to their long-term benefit.Paint, Light Fixtures: These can be a bit nuanced.

In terms of your grandfather living there as long as he's not the owner having a dwelling fire/rental property insurance policy is appropriate.As @Greg Scott pointed out he should have a renters insurance policy whether or not he's actually paying rent.In terms of liability coverage, that depends on what you have to protect so there's no one-size fits all approach.

If there were any written agreements between the developer and either realtor, the terms of those agreements would come into affect not that complicated.