Your kind of in a pickle, if everyone in your camp is using the Rhino and you want to talk with them your probably going to need a Rhino. In my opinion the Rhino is kind of worthless for communication unless your group stays fairly close together.
I have never bought into the Onx coolaid and use the earthmate app which comes with the purchase of an Inreach for all my mapping needs. Earthmate shows property boundary's and has all the topo and photo maps that I need.
If you use your phone for GPSing there is no need for the 66i, it looks like a great unit and if someone wanted a backup GPS unit to there phone it would probably be a great option.
For me my old Delorme SE Inreach, phone and Earthmate app get it done just fine even hunting Wyoming checkerboard lands for antelope. Once the SE gives up the ghost I'll get the Mini unless theres something better on the market.