The time spent in the commercial cryovac bag is considered wet aging. While that period does help tenderize the meat I personally would not subtract that time from my Drybag time. Reason is the Drybag permits the aging but also the removal of the tasteless water. That concentration of the beefy taste is what creates the WOW factor IMO.
As for using a protective barrier as you asked with a bone-in sub-primal – yes that will work. Just be careful that you position the meat “at rest” so that bone points don’t come in contact with the shelf so as to prevent punctures. I do want to raise a question though – most people opt for the boneless cuts because they do not have a means of cutting through the bone at home. Also even if they intend to separate the meat from the bone after aging then keep in mind the meat under the bone will not be as dried as a boneless cut.