If your coolant is low (due to it being all mixing with the oil) then the fan wont come on as the sender is in the neck of the radiator.
1st is usually hard to engage, either do it when your still rolling or as many do use your hand when you have stopped!
Water pump seal is available on its own or as part of a kit, You shouldn't be riding it as it is until you sort that water pump seal or you will create more problems