>>10477332Your best bet probably is swapping pieces as
>>10477655 says.
I have some Picco Neemo shoes bought from hobbysearch. They are mostly a bit small for figma feet. You can make them work though either by sanding the feet smaller if you dare or making smaller feet from putty. Since they won't be visible it doesn't need to look good.
In the picture the two pairs of boots on the right fit straight on the figma feet, but the shoes on the left were too small and needed these methods. I don't have any snail shells to test them on.