Concierge Service

Does concierge service fall under the category of the premium feature of "Hosted Website"

No, Concierge is separate. The Hosted Website is your own website advertising your properties, allowing guests to directly book with you without having to always go through some other channel (Airbnb, VRBO, etc.)

https://www.ownerrez.com/support/articles/hosted-websites

Concierge service is our staff directly helping you get your OwnerRez account set up and configured.

https://www.ownerrez.com/support/articles/concierge-setup-overview

Sounds like that's what I need. I can learn to use the site and software over time, but I'm not techie enough to just jump right in.

Re: Channel Management - Is this a feature that goes beyond syncing booking calendars, or is it required in order to have my different listing calendars sync whenever a booking is placed?

Two way iCal sync for booking calendars is included in the base plan.

Channel Management refers to deeper integrations like API where you can push photos/descriptions/amenities and get bookings automatically. Some channels have a 5 property minimum for API so we also have a channel bridge tool for Airbnb and VRBO that lets you push rates and import full booking details with no minimum properties.