6 beeps is not an overheat alarm, a solid tone is, and it can come from either the engine cooling system OR the compressor.
Was your telltale present and strong? If the compressor strainer is plugged it will starve the compressor for coolant and cause an overheat alarm.
There are only two specifications for water pressure at
idle it should be 1 - 3psi and
WOT it should be 12+psi. There are no specifications for anything in between. Likewise, coolant temperatures will vary depending upon lake surface temp/load/engine demand so there is no "normal".
The 2.5L Optimax has 143° thermostats which is when they begin to open, so idle temps (in or out of gear makes no difference) in the low to mid-150s is normal.
If your dealer didn't also replace all
3 gaskets when servicing your water pump that may still be the source of your low water pressure problem -
Water Pump Replacement
Engine needs to be scanned to determine what caused the 6 beep alarm.