About the "Top 500" paragraph
I wanted to add a detail in the "Top 500" paragraph. I believe that one of the requirements to be eligible for Top 500 is to have at least 3000 SR. However I wasn't able to find a source on this, it's just that if you look at the current leaderboard for Competitive 3v3 Group Elimination, it looks pretty obvious. There's no one under 3000 SR on the leaderboard, even though there aren't even 100 people currently on it, so anyone doing 50 games, even placed in bronze, could actually be Top 500 if diamond wasn't a requirement. Can anyone confirm this? Is it stated on any official source?
Also, since the June 26, 2018 patch: "[PC] Players must have Blizzard SMS Protect enabled on their account to be eligible for the Top 500" And you need to enable it before doing 50 games, any games played before that won't count for the 50 games required.
Edit: It appears that, even though it isn't mentioned anywhere, you will drop from the Top 500 leaderboards if you don't play a competitive game in a week. At least that's what happened to me in Competitive 3v3 Group Elimination; I came back from a 8 days vacation and I wasn't on the leaderboard anymore, even though my SR was high enough to be ~top 250. It also has nothing to do with SR decay, as there isn't any decay system for Competitive Arcade modes, and my SR had not changed. Can anyone confirm the exact number of days before this happens? It sounds likely that it's seven days, but as I was away for 8 days, I couldn't see when it happened exactly. Note: I found a thread on the official forums (us.battle.net) where 2 people had the same thing happen to them with Comp Lucioball: /forums/en/overwatch/topic/20758846621
"Lastly, you will drop out of the Top 500 if you don't play at least one competitive game for 7 days in a row, even if according to your SR, you should still be on the leaderboard. This also happens in Competitive Arcade modes, even though there is no SR decay in those modes. If you play one game after dropping out, you will be back in the Top 500 (assuming your SR is still high enough)."
--> Now remains to determine whether you have to play at least 5 games each week (to avoid reaching the point where your SR would begin to decay - if there were decay in arcade modes), or whether playing only 1 game each week until the season if over would be enough. I'd assume you'd have to play 5 games a week.