To decide what model to purchase, I think it's nice for new skaters or skating parents to involve a coach, as coach will better describe the skater's level, style of skating, likely progress etc. I assume most coaches would not mind serving an advisory role if the pro shop is reasonably close, appointment time fits schedule, and the coach's time reasonably compensated for. But I rarely see coaches accompanying the skater's family for fitting at our pro shop, guess coaches usually trust our fitters do an excellent job.
If pro shop is at the rink and coach can see me skating right away, yes I'd ask coach to be present to help deciding if the blade alignment looks right. I think my rink is too far away from the pro shop for me to bring coach along.