Adding gas water heater and furnace. Do I need to upgrade gas pipe?

I live in a recently built home in Loudoun County, Virginia that has a gas furnace but strangely has an electric water heater. I want to change the water heater to gas and change the second furnace for the second level to gas. The gas meter to the house is 250K BTU. The main gas trunk line is a 1” pipe about 25’ long with several elbow & T fittings (see pic below). There are three branches to the main trunk.

Branch 1 is a ½” pipe to a 45K BTU cooktop. The line is about 7’ long
Branch 2 is first a 1’ pipe about 10’ long then elbows down over a metal beam and reduces to ¾” pipe to supply a 75K BTU 93% furnace. The ¾” section is about 6’ long
Branch 3 is a ½’ pipe to a 35K BTU gas fireplace. The branch is about 20 feet long.

All the pipes in the house are black iron pipes (except a small section that connects to the cooktop). I want to tap Branch 2 to supply gas to a new 42K or 65K BTU tank-type water heater and a new 24K 90%+ furnace. The branch already has a 75K BTU furnace on it. Do I need to upgrade any existing gas line in the house to accommodate the new load?

A rough drawing of the plan is provided below. The dotted lines represent the new additions that I want to add. Thank you for your help!