I'll need some more info here. Please post some of the code you're using for updating the statistics. It should work as long as the players are logged in. Whether they're a guest or not does not matter.
You don't have the extension names set properly. The extension name is the name used by the extension, which means that when you -- for example -- call gms_statistic_get, you'll need to provide the extension name. The title of the statistic is only used when displaying it.