On this job, we wrapped the sheathing before trimming out the chase corners with Mira-Tec treated composite trim.
We replaced the original fiber-cement lap siding with 5/16-inch-thick HardiePanel stucco-textured fiber-cement panels.
I don't like the look of too much exposed step flashing, so we covered the steps with MiraTec trim installed at the pitch of the roof, maintaining an inch of clearance between the trim and the shingles.
Some builders try to hide step flashings completely, but that's a bad idea, as this photo from another job shows.
We replaced the existing plastic vent hood for the fireplace's makeup air supply with a metal one, mounting it on a PVC block and cutting the siding panel around it.