Does anyone know at what point teams can trade players now? Specifically, Alex Kerfoot's modified trade clause doesn't go into effect until July 1. Can he be traded now? Is there a trade prohibition while the playoffs are still going on? Is there a trade prohibition until July 1?

No prohibition that I know of. The trade deadline only applies to playing in the playoffs, but any team can trade with any team right now. Yes he can be traded now.

Thanks! That's what I thought, from the trade on March 28.

The rule on trading players is that trades after the deadline are permitted, but any player involved in a post-deadline trade may not play in the NHL until the next league year. The most recent notable trade after the deadline was Adam Fox to NYR, which happened during the second round of the playoffs on April 30, 2019

https://www.capfriendly.com/forums/thread/219845