Will Strangehaven plot be linked to Shards plot?

The answer to this one is yes and no. The Strangehaven world background is the Shards world background set in the same timeline and characters may be played in both games, hence there will inevitably be crossover between the two campaigns. However, Strangehaven is intended to be a standalone game, running independently from the Shards core events. It will have its own plot, NPCs and storyarc, but events and actions originating from Shards may influence Strangehaven and happenings in Strangehaven may impact on the rest of the Shards.