What does the green bubble at the top of a champion's avatar mean?

Does leaver buster affect you if you leave at the champion select, but have not yet started the game, thus not creating any inconvenience?

Are the 3 refunds per life or per year?

Is it horrible if at level 27 I can only play Support and ADC, failing badly in other roles? I don't like jungle, but as for Mid/Top I simply haven't found a champion to suit me..

If the green bubble is there, the champion's ultimate is up. If it's not, then it's on cooldown.

No, you don't get punished for dodging in champion select, but you do have to wait a few minutes before you're allowed to join again, the time gradually increasing the more you dodge in a short time period.

Per life as of now.

Just try out whoever. Doesn't really matter unless you want to get into ranked.

Finally, that bubble's been making me wonder
Yeah I know you have to wait. It's better to wait 5 minutes in peace than condemn yourself and your party in a 20-40 minute game full of frustration and embarassment for everybody.
And I obviously would not go in ranked unprepared. I plan to postpone it as much as possible.

Thank you very much!

League, and in general all other MOBA games are pretty complex.
You have to learn your own champions limitations, its strengths, other champions limitations and strengths, items which fluctuate every game and change your own champion and others, along with how the average human player will react to an action, friendly and enemy.

You can be level 30 with 1000 games played and only just starting to get the hang of one particular role, most of the Pros only get it because they've been playing games similar to LoL for around a decade.

So don't worry if you're not good enough as you wish you were, or if you can only play one role. You'll get better with time and ONLY time

Your first few questions have already been answered, so I'll just touch on the last one. Getting good at a single role takes a lot of time. Sure you can get the hang of it after a few games, but the actually be good at it takes practice. When you do play these roles, don't just play around, actually focus on what you can improve on. If you are playing ADC, make sure you focus your energies on last hitting minions. If you are playing support, get to know your abilities (and who you are laning with) and focus on ways you can help your partner, harass the enemy, and be effective. One thing I will say though, a lot of it comes down to finding the right champion. Playing any role as a champion you don't enjoy or find fun kills it for everyone. So if you find someone who fits your play style, then play the **** out of them.

People like to throw around the phrase "practice makes perfect." Well that is utter bull****. Practice with purpose and focus, now that will make a difference. Just doing something repeatedly doesn't always helps, as much as doing something with the intent of improving.

Thanks guys much appreciated!