RE: 何か vs. 何でも
何か means “something (that is either unknown or unspecified, but) specific.”
何でも means “anything/everything (nonspecific).”
RE: This review
何でも feels… weird here. It’d make the sentence seek a specific answer while using a nonspecific question word.
“When you go to Japan, is there anything you want to eat?”
This is arguably the most natural-sounding way to phrase the English translation of this Japanese sentence. We could change “anything” → “something” to more accurately reflect the Japanese sentence, but the problem I have with this is that doing so may only teach us how to translate “strange” English phrases into Japanese, and keep us from realizing the subtle adjustments we need to make to take natural English sentences into natural Japanese sentences.
I think we should throw a warning (and not mark the user wrong) for なんでも here, possibly even giving the “something” translation for the answer at that time.