It's easy. Use 1/2 PEX line to back of fridge, install s/o valve with a take-off to fridge( usually 1/8 flex line)
Dishwasher line is hot water. Tie ice maker into 1/2 inch cold line going to kitchen sink.
I don't think so; generally there is a line that runs from the water source (sink or what have you) that should have a shut off valve located somewhere along the line. You should be able to see where the line connects at the back of your refrigerator and hopefully track it back to the source. It's frequently under the kitchen sink. Hope this helps!
It is where the supply line is attached to a water line. May be under the kitchen sink or in the basement under the refrigerator in the closest supply line. Should be a hot water line. Hot water because most of the minerals stay in the water heater and the water in the supply line will be cold from sitting. Someone may have put a shutoff at the floor behind the refrigerator, but I doubt it.
Snake the line to unplug it
Those are hard water stains. You need to wipe your sink dry after use, if you have hard water.
Because both sides of your sink are connected to a common drain line, and the common drain line is slow.
A PVC ball valve, and add a threaded coupler to attach the supply line from sink.
It's pretty hard to avoid.
the drain line is completely or partially blocked, the drain line needs to be snaked out. the disposal is forcing what water it can down into the pipes but if there is an obstruction the water has no place to go but back into the sink.
Additional shut off valve, below sink or in basement. Incomplete pipes not tied into bathroom sink line.
An easy way to check your water pressure is to install a gauge using an ice making line kit tapped into an easy spot like under the sink. Just put the gauge on the end of the ice maker line.
Kinked hose or obstruction in the water line between the wall and the faucet.