Re: Ultra light b&c stocks
Without actually looking up weights for any of your components, yes, I do believe you should reach your weight without problem.
I had a rifle built several years ago using a Rem 700 long action, #4, 24" Pac-Nor barrel with a brake on the end making it 26", and a McMillan Griffin & Howe pattern stock with what they called "light" fill at the time. The rifle weighed an even 7# bare.
I hope you will show us what you end up with when it is completed.