A one button reset spec'd. I would likely just bring the safeties into a PLC and have the one button reset to come into the PLC as well. Then I would back up that series of botd's with multiple other safeties in the logic.
What about letting it alarm out - Freezestat/Powerfail Alarm Requires Manual Reset!
Not ideal I know, but how often do they have power bumps? Don't know your climate, but this may/may not be acceptable in case of a long weekend.