I suspect the identities of the specific items around Wally as he falls are not relevant to the plot. If they were, they would have been drawn more clearly.
Agree! It seems as if all the time from before Wally and Company met Dr. Amesworth on the beach, to crossing the boundary to dunk in the ocean, all the time on the ocean and in the lighthouse was no more than a few hours, and maybe only a few minutes, for these topsiders.
I suspect the identities of the specific items around Wally as he falls are not relevant to the plot. If they were, they would have been drawn more clearly.