The problem with the combo cart is it does have it's own box + literature and (I think) it's own barcode (which makes it different then just the Mountain Bike Rally release with no Speed Racer). To me, that qualifies it as it's "own release", and something someone (back then) could purchase. Granted it may have only been available to people who owned those fitness bikes...? But still, people COULD call a # or send off a check/money order and have the game shipped to them all wrapped up nicely, (which is how you see so many sealed copies for sale as opposed to opened copies).
The competition carts did not come with any unique paperwork, just a clamshell with printed artwork from Blockbuster (some people go ga-ga for) from what I've seen. While you could order them from Nintendo at one point, they were never given their own box/barcode/manuals, so are more side-bars to a complete set (IMO). If they were put in a store setting (Toy's R Us or Kaybee type deal) back then, Nintendo would've produced so kind of box/manual to complete the package.
Same with the MAC's carts which were designed specifically for the military and never meant to end up in civilian hands, (which is why they have warnings/numbers to call on them in case they DID get off bases). I don't consider them part of a set, either.
Having said all that, though: if you get far enough into collecting for the SNES that you have everything BUT MACS/MB-SR/Competition carts ... well that itch may have to be scratched regardless.