I'm happy if I get a 1 star score in most levels, haha. I don't think you can call this a bug. If the level can be passed then I'm sure that you can get any score with the right kind of moves. Keep it up though, if you're heading for 3 stars in each level.
It can happen sometimes. The connection can drop, the game can crash, it's never nice but all you can do it play the level again. I hope you can pass it again!
It's always possible, it can just take a little time! haha. It's a tricky level to give any tips on, I had to watch a lot of videos to find the best tactics for me. Maybe you can do the same: https://www.youtube.com/watch?v=GEsha-Z0gvU
I know that the little circle is the loading screen. Check out the video that the mods posted, it might help! https://www.youtube.com/watch?v=OESCE4Jj2tU
On Facebook, you can't unless you have another Facebook account. On the mobile, just delete the app and you'll have to start again when you re-install it.
You need to mix them with the water drops! Check out the first few moves in this video for an example: https://www.youtube.com/watch?v=6SG9w6qvnXI I hope this helps!
I deleted my Candy Crush game once and I lost my progress as well :( I know that you can get it back if you play on Facebook. Just go into the game and re-connect, it should return your levels.
You should be able to get your levels back by re-connecting to Facebook as that's where your progress is saved. Just connect again in the app and you should get them back.