"Ed Pawlowski" wrote:

which will eventually be capped off and enclosed in the wall.
Is there anything wrong doing it like this?

I'm not sure about capping a gas pipe in a wall. I'd be afraid to do that
and get a gas buildup in there.

The other problem is that you should have a licensed plumber check your work for
code compliance or you will have a problem when it comes time to sell the house.
I'd be concerned that you have a large enough supply to run both the furnace and
HW heater at the same time.