Sync is working for me although it generally syncs what it wants when it wants.
Can you check here sync.opera.com and see if anything has been synced there? You can access your bookmarks and history there. Passwords will be encrypted so you can't look at them, but they should be there as well along with any devices. If there is, then you can manually add your bookmarks to your devices.
Offline pages will not be lost if sync is reset. They are stored on your device wherever Opera is stored and should remain there as long as you don't uninstall Opera. That is the one thing that Opera doesn't sync I think.
As for Speed dials not syncing, you have to manually import them they will not appear by themselves. If I remember correctly, Bookmarks and History are the only things that show up instantly across devices. Tabs and speed dials can be accessed on Android through the tabs menu (Numbered square on top right). On desktop/laptops synced speed dials from other devices are listed under bookmarks --> other speed dials and can be added to your desktop/laptop by copying and pasting them to that device's speed dial.