Team Canada's WJC camp is absolutely stacked. Strong draft year for Canada combined with several players made available due to the late start to the NHL season that would have otherwise not been made available.
Maybe they consider taking Greig as an energy guy for the 4th line, but I imagine he'll be on the outside looking in. Probably plays in the following tournament though.
Yeah, there is a lot of talent this year. As you said, his best chance at getting in will be his versatility and style. There are 14 f's at camp who were drafted ahead of him, and the only guys who are in his age group who were drafted after him are Bourque and Goncalves, as far as I can tell. That also doesnt include guys like Rees and Beckman - guys who are older than him and have developed at a high rate since being drafted.
His ability to play C or LW and his pesty, pro-style game will definitely help him, but if it helps him enough to crack the squad is not something I'd be confident about. Next year he should at least have an inside track, especially since the 2021 draft year is not as FWD heavy, plus some guys on this team will be in the NHL.