Seems no friends will be shown as online unless the account is deleted and recreated within miranda upon restarting the application (win 8.1 pro x64, miranda nightly 32). A status change from a friend on the friends list will cause them to show up, at least I think this is what makes them be shown. I've also had an issue where people that were in a recent game with me will show up in the friends list. Haven't looked too much into it.
After using it more, seems this is only for a while when first updating? I'm not sure as my contacts show up now without an issue.