WW, you shouldn't even attempt to beat with Flash. It's his worst matchup, just use someone else. As for Red Hood, Flash actually beats him. Red Hood has to use highs a lot in neutral, and you can low profile those and get a full combo punish. Red Hood also has no wakeup, making him very easy to pressure on oki. His only real options are Fatal Drop, or delayed wakeup, but a double RMS will counter both of those options on a read. Also, Flash severely outdamages Red Hood, and Red Hood can't get his mines out and start up his zoning because RMS 1 will punish mine on a read. I also believe that Lightning Punches punishes his overhead trait ender, meaning all of his trait options are punishable by Flash. Red Hood essentially has no way of executing his gameplan against Flash at any range, and gets shut down because of this.