sorry i cant help with info needed.....it could have been custom made kit, only available to the vendor.....so i doubt you will find a datasheet anywhere.
-also, it could well be a companys IP, so to speak, and they wont share it with anyone else.
If you want to turn lights, fans , solenoids etc on/off then transistor switchs are smaller and cheaper.
if you want to control current in a solenoid efficiently, then a switch mode solenoid driver is needed.
i can't see why a coffee machine needed so many relays.........but maybe there was an isolation requirement between the activiating circuit and the actuating circuit.
Relays aren't that great as switches, they corrode eventually, they often need a minimum current to stop corrosion of the contacts. relays also tend to be expensive.
But relays do offer a low contact resistance i suppose......but fets are also low.
relays also bounce on contacting....whereas fets dont