1) WCH 2010: Czechia won, 3 NHL guys. 2019: Finland won, 1 NHL guy (I believe). 2022, Finland won, 3 NHL guys or so. In both 2019 and 2022, Finland won vs. Canada with full NHL roster in the Gold Medal game.
2) AHL is a specific league which is often drastically overestimated in Europe. Notably, the teams are usually playing a very fast but intuitive hockey with little tactics. This is why a player's success in this league doesn't guarantee he would be capable of playing a tactically more developed game, and vice versa.