There is no way to link to a box score directly at the moment.
You haven't retired the player. He can continue to play on your team; It's simply that no one else will be able to wear #13 ever again.
Correct, the stats (total, average, and maximum) are all based on regular season club games only. Many sports, including the NBA, tally postseason statistics separately from a player's main stats. It also made sense to exclude NT, cup, scrimmage, and PL games, because those often include matchups of teams with dramatically different skill levels. To exaggerate the point, a 50-point game against a bot team in the cup probably isn't a moment worth memorializing.