With spray foam you also get a vapor barrier, which you need. And by filling entire rafter bay, including strapping or furring, you don't have to worry about venting. Foam doesn't make it more "final" than any other option. Its your best bet in this situation.
Foam walls too, use minimally expanding around windows and doors. Mite wanta add horizontal blocking a few inches below windows. Mask off windows and gaps around windows, spray main foam, which can expand enough to bend window frames, then fill gaps and spaces with minimal foam.
What is panel below window? If frame dimensions are important keep high expansion away from sides there too.
Think about adding a few more outlets while electrician is there. Easier to do now than later. They're never in right place. You can never have too many outlets as long as you don't overload circuits.
Any insulation may interfere with light cans. And light cans can interfere with vapor barriers. Be sure to install insulated, sealed cans that can be in contact with insulation. Install outer can, and mask off opening B4 spray.
[CENTER][FONT=Comic Sans MS]Measure twice, cut once.[/FONT][/CENTER]
[CENTER][FONT=Comic Sans MS]Look at the nail, not the hammer. Watch the fence, not the blade.[/FONT][/CENTER]
[CENTER][FONT=Comic Sans MS]If you hook your thumb over your belt you won't hit it with the hammer or leave it layin on the saw table.[/FONT][/CENTER]