Maybe the LRP would be a good idea. But the Water Ladders would be difficult as some services have different names for trucks. Like the 9m ladder one. Some have 10.5m etc.
Some areas call trucks Pumps/Pump Ladders. WrL/WrT there are too many variants and would get confusing in game. And the water tank sizes would also vary depending on what the service have ordered.
My area has LRPs for rural locations. We have I think 2 or 3 Mercedes Sprinters with rear body locker setup and a 4x4 Land Rover for forest fires. then the general Trucks vary in size depending on the location.
In the main city/towns we have Large Scania Trucks then going into more rural locations we have slightly smaller MAN Trucks.
Our water carrier is a bulk foam and water carrier so dual purpose.