That sounds like a fine setup! You didn’t mention a batch brewer in that list and that will take care of brewing and hot water dispensing in one unit. I’d suggest a Curtis D500GT or something from Fetco.
Your best guidance on Water treatment comes from LaMarzocco itself. We filter our water to spec and use that throughout the shop. You can find LaMarzocco USA’s water specs here It may be a tad different based on where you are in the world. We had a local water filtration company build a setup based on our water source, from which the output matches spec. So your filtration system may need to be modified if you move locations/water sources.
Good luck!