Installing header remodel

[rebar]

I would like to install a new construction window in a split level finished house above the front door.

I will need to cut two studs and need to know if the trim or jack studs need to be installed from the bottom of the header all the way to the bottom plate requiring me to remove more drywall than I expected. Or can I screw or bolt on a trim stud to support the header which does not extend to the bottom plate? This new header will support the top plate and a few roof trusses.

Thanks

[Windows on Washington]

supporting the roof trusses I would opt for running the studs to the bottom plate in the floor.