If you only put in 100k (the amount to buy the original house) and the rest was all appreciation of property- the whole gain ($350k) would be subjected to capital gains.

Is there anything they should be covering?

It'd just be one less person to hold accountable if things go bad or they end up leaving damage/money owed that isn't covered by the security deposit when they move out. 

Yes, if it was obvious those occupancy limits were designed to discriminate against a protected class, and you/your property was subject to fair housing laws.

Additionally, what if I or a contractor had an accident and received bodily injury, would we be covered under the homeowners insurance policy?

I'm ready to start looking at properties and identifying a contractor/s I can work with, what type of insurance will I need to make sure my business is properly covered and does that have to be renewed/added to each house I flip or is there some sort of umbrella policy that I can add and remove properties as my business progresses?

Depending on the carrier this can be exclusive to Category 1 and above Hurricanes or it can also include Topical Storms and/or Tropical DepressionsTropical Cyclone - A little broader in that it will generally include any storms that originate from the Gulf of Mexico regardless of the status (hurricane, tropical storm, etc.)Wind and Hail - The broadest in that it not only covers any storms originating from the Gulf of Mexico but any wind and/or hail damage regardless of where it originated fromThe reason why you need to pay attention to this particular deductible is because it will be percentage based deductible; keep in mind that this means that if your cost of insurance on the dwelling increases, so does the deductible.

This gain, maybe taxed at favorable capital gains tax rates.Furthermore - you will be required to report the commission on your schedule C which may be subject to ordinary income tax rates + self employment tax.

I would contend that if, as you say, the rent barely covers the mortgage, you will end up losing a lot more than that over time by holding onto the house.Repairs and maintenance on a house are not cheap, especially on one that is 100 years old.

I've nothing to add, you covered it.