@Sherri214 Sone answers below
As a host can I block out times that I may want the place available (at no cost) for my family members?
Yes you can. You can also take non Airbnb bookings if you want.
How much on average will this increase my home insurance cost?
This varies by country massively. Just ask for a quote. Only a few companies will cover short term rentals.
What about hosting a home with a pool?? An indoor fireplace? Can I be sued if someone is injured or drowns on my property??
You need to make sure you have sufficient liability coverage
If it is not a good fit for me can I cancel my listing and get off airbnb without any issues? (honoring all reservations first of course)
Yes you can
Anyother thoughts or concerns, recommendations I may not have thought of??
Far to many to list here. Suffice to say short term rentals are hard work but we have done very well out of ours for the last 3 years.