Have you tried printing after “Make Array” but before the FELoop? You can also try converting a literal to an integer before plugging it in. Making Literal #'s isn’t usually something I’ve had to do alongside arrays before, but I can make suggestions. Generally you want to convert things into variables, though, before pushing them into arrays.
As far as ref vs copy, any work ON the array to alter it is a reference, as far as my experience. If you need to get a copy, promote the array into a placeholder solid variable before doing so. Then you just use “Get Copy” and plug in the array and index int.
Generally if something made with “Make Array” goes more than one node further, it’s left behind. Good for things like declaring things to seek with sphere traces etc.