I like minimal quilting; altho the overly quilted quilts I've seen on here are lovely, I think the quilting overwhelms the piecing. You have a great idea about the fleur de lis in the larger diamonds; if you outline your diamonds 3/8" and then do the fleur de lis I think this would be filled in nicely. Also, since it's for your DH this is a less feminine but attractice quilting pattern.
(I hope I didn't offend by saying I don't like heavily quilted quilts--sorry it's just a personal preference).
You are so much like me-- I don't trust my own judgement on designs or color selection,etc. You've made some great choices--jump in!!!