I hesitated a good bit before posting this, but I think it needs to be said. I don't believe this is going to work out for your client. I'm not saying you aren't capable of building and configuring a machine that does exactly what you said it needs to do, or that your client won't be able to operate it when first installed. I'm saying that one of two things will happen. Either you will spend a HUGE amount of time keeping it running well, and you or your client will be unhappy with the billing for said time, or your client will use it happily until it quits working because of an update or something stupid, and it will be tossed aside.
This is not a set it and forget it type of installation, and remote support will become a huge headache.
If you said YOU wanted this system for your house, you were building and maintaining it all, then not a problem. Doing this same thing for a paying client? No way.