The projected rental income wouldn't cover the mortgage and HOA at this time.

You will need to cover perc tests if needed for each lot and then hire a surveyor to draft the ANR plan for submission to the town, just treat wetlands as sacred Indian burial ground - stay away from them and your costs will be very low.  

The part of the home you live in can be covered under an HO3 (homeowner’s) policy, but the rented unit needs to be covered by a landlord or dwelling policy like a DP1 or DP2.

Each lot is assessed with the taxes to cover such cost and they are paid monthly for the first 15 (give or take) years as part of your mortgage payment.

can you share a picture of this out of curiosity. 

If their policy ever lapses or is canceled, they are automatically enrolled in my master policy and covered. 

I think #2 covers 90% of the work, BUT there are people whose debts are out of line with their income.

The main factor is will rents cover the debt liability and can you sustain 3-4 months of no income to cover the debt? 

STR management is 20-25% (I would recommend self managing or getting a VA), since income is higher you could probably get away with 5% for maintenance / cap ex but remember you need to cover utilities and cleaning for these units which drives up costs.

To get a full picture, there are many, many questions you need to know the answer to, and this is only a partial list.