Cleaning up engine bay for paint questions

Hello, I have been Sanding and sandblasting the engine bay in my 72 scamp to prep for the motor I'm building and I have some questions on paint and items I can remove to clean up the look a bit.

I'm using the kbs rust paint kit on bare metal and high wear areas and what to know what paint and primer is best to cover the entire engine bay. Was thinking of using Hemi orange engine enamel for it's heat and chemical resistance. Will this have any reactions with the kbs rust seal? And is priming nescissary if everything is sanded with 320grit sand paper?

What have you used to paint the brake booster, wiper motor and blower motor?

And what is this steel line that runs along the fuel line and up to the rad support? Breather line for the tank? Can I remove it?

Thanks again for the help guys! Looking forward to your replies.