Yes.
A tee is a plumbing fixture with one inlet and two outlets, or two inlets and one outlet. A cross is a fixture with one inlet and three outlets, or three inlets and one outlet.
Install a checkvalve
You definitely tile AFTER the plumbing ! =-You wouldn't want to look at all that plumbing running outside your nice tile job would you.
Go outside and look where your sink is, there should be a plumbing cleanout near where the sink is, this is so the plumbing can unstopped if it becomes plugged.
"How do you unhook a hot tub that was connected to an '''outside electrical outlet?'''" .... Just unplug it
Yes BUT not an outside wall
It saves you going outside to a little shed
I don't know about the outside diameter of the hoses but, the outside diameter of the heater core inlet and outlet tubes are 3/4" (inlet) and 5/8" (outlet).
By plumbing codes, no.
Not if you are in area where there is a chance of freezing.
You must mean in DRAIN pipes. -It can not be used in plumbing pipes.