I'm lost as well. The first resolution shouldn't put extra copies out. The way I see it, nothing put copies out except the initial cast, thus there shouldn't be any checking except for the initial cast. When the spell is casted, it sees 5 creatures and adds a copy to each nontargeted one on the stacks. The first copy resolves (does not check for other creatures as it was not the cast) and makes a duplicate of himself. The second copy resolves (does not check again since nothing prompts it to). Ect for 3, 4, and the initial spell 5th (does not check as it's passed the "cast" and on the stack) . New creatures etb can be placed between those resolution, but doesn't change anything.