LCS Summoner Names

I have a question about the usernames used by the pros in the LCS. They always have the team name abbreviations in the title, and it made me wonder...that obviously can't be the account they started with, right? Like, I have my account, and I play with this account and stuff. So, when they go pro, do they have to change their summoner name or is it an all new account? Also, when typing pro usernames into the search bar in game, no results come up. Do they have like protection against 739479 friend requests? Lastly, the team names are kinda weird, and a lot end in 'Gaming'...is there a reason for this?

Sorry if these are all kind of stupid questions, I don't know much about league as an esport and these questions have kind of been bothering me for a while.