I have a Honeywell VisionPro 8000 TH8321R1001 thermostat. Is this compatible with my panel or with alarm.com for remote control via wifi through my alarm.com access?
That thermostat would not be compatible with Alarm.com. The only non-Z-wave thermostat that is supported with Alarm.com is NEST. Compatible Z-Wave thermostats would be dependent on panel model, a list of which can be found here as well as Alarm.com compatibility.
Note that some Thermostats in the above list are no longer Alarm.com compatible, you will want to check out this Alarm.com compatible list of thermostats as well.