My kitchen is currently apart so while there's plenty of room to work
my wife
wants an under the sink water filter system put in. I was looking at
some double filter units.
The filter will go to a seperate faucet.

Will this work:
Put a tee on the cold filter line (after the cut-off) with a threaded
male adapter on the output that will go to the water filter.
Use a metal jacketed hose to go from the adapter to the filter.
Another one from the filter to the faucet (or use hoses that come with
unit)

If we don't actually install the filter immediately, then is there an
adaper that I can screw onto the male adapter to cap the line?

thanks