Not sure exactly pidge, but they do send the international ones out first for just this reason. However, one of the answers to an FAQ on the website says:
"If your Number Pick Up Card does not reach you before race weekend, please be sure to bring a photo ID with you to Number Pick-Up at the John Hancock Sports and Fitness Expo located at the Hynes Convention Center. Go to the "Replacement Number Pick-Up Cards" booth near number pick-up, show your valid photo id, and a volunteer will print a new card for you. You will use that new card to pick up your number. We are requiring that all participants claim their own bib number at the John Hancock Sports & Fitness Expo during normal expo hours. Friends or family will not be allowed to claim your bib number for you."
Let's change the approach then. This will be a good turning point in the project... This will be designed for a triathlete who wants to be able to clip in and run without the faff of changing shoes during transition. So instead of wearing the shoe during the swim, they put it on after the swim.
Is that better?
There have been attempts to use running shoes on the bike before - google 'pyro platforms', essentially something that clips onto a regular pedal to create a stiff platform and toe cage for a running shoe. Some duathletes use them, especially in shorter races but there's a compromise in that there's still a relatively soft, flexible layer or running shoe between your foot and the rigid 'sole' of the platform.
Like FB says, your best bet might be swim-run where some manufacturers are looking at designing specific shoes and competitors are already customising existing designs. I suppose the ideal shoe would need to run like an offroad trail shoe, but with some buoyancy built in for the swim, be streamlined to reduce drag in the water and have some drainage to let water out after the swim. And be comfortable enough to use without socks with no blisters, even when your feet are wet.
Think of the Marshall's and the extra time they will be on the course if you introduced 2 waves
20 minutes max. That's assuming that the slowest runners are in the second wave. Last time I marshalled a 10 mile race I was out on the course for over 2 hours anyway. You'd make it condition of the second wave entry that marshalls on the second half of the course will be withdrawn after the last runner from the first wave has passed.