QA1 Crossmember Question

Good Morning,
I have been doing some reading on the QA1 crossmember and had a couple questions.
Working on a ‘67 Barracuda, factory 273 crossmember with a ‘72 360.

First question will my existing motor mounts work? I ordered them from Mancini several years ago telling them I had a ‘67 273 crossmember and I wanted to bolt a 360 in its place. I can’t seem to nail down which mounts the QA1 crossmember requires.

Second, QA1 instructions say their sway bar is the only one that will work.
I have a new in the box hellwig part number 55917. Will that bolt on?

Third, I thought I read a post about another 67 and they had to use a 68-72 idler arm. The one year only 67 arm didn’t fit. Just want to confirm that’s the case.

I also have a pair of Firm Feel upper control arms I plan on using.

Just want to have all my ducks in a row and all the parts in the garage before I tear the car apart

thanks again for all your help