“since Rav Belsky held that kitniyos is a safeik chametz.”
I’m not sure what that means. He held that corn was safek chametz? Or was the concern that a kitniyos product (like ketchup contianing corn syrup) since by definition it dindnt have PEsach supervision, so memeila there is a safek chametz. The latter is a possibility the former is not, though it wouldnt apply to putting corn in soup.
“please don’t overlook that things may not botul if they are B”EN, easily recognizable.”
There is no need to overlook that. You peek in scoop out the corn, and the rest is mutar and can be served at the seder. (again assuming it is batul note: brov not beshishim).