You've got a few options. The EL041 thermocouple solution would be the most economical as this can take readings from 4 thermocouples. The only problem is that we do not recommend using thermocouples longer than 10 meters as the signal can degrade. As your stores can be as far as 25m from each other it may not be a good solution.
The other option is to use 2 or more EL001's. These can take up to 3 thermistors (EL015) each, the thermistors have either 5m or 10m cables.
The third option is to use 4 EL026's. This will also give you humidity readings of each store room.