deputy-- I really don't think Monoprix is going to be better for you from the English standpoint. I could be wrong though, as I haven't been there. Petit Casino definitely has some English labels, yes. OR just head for Carrefour (any of them) and they will have plenty of English labels.

But it doesn't matter whether the suitcases fit in the trunk or not, PLEASE don't start off your vacation by taking a big risk like that, and getting all your stuff stolen. It's just not worth it.