If you have newly added the fields, you will need to refresh the field list in the index pattern. Go to Management > Index Patterns and select refresh option. If you had already done that (and it sounds like you have), could you go to the dev console and try to retrieve the documents from your index? Are the newly added fields shown there?
GET /<your_index>/_search
{
"query": {
"match_all": {}
}
}
If so, next thing is to check in Discover itself that you have "Hide missing fields" option deselected.
