Just checked the Ponant website for their Iceland tours . They still are showing sailings for the two dates (6/16 and 623) before Tauck starts sailing with them on 6/30.
I'm holding onto about a 20% chance that this tour happens.
As of now Iceland isn't allowing foreign visitors, but they say they will reassess about May 1st. I would expect to determine for sure if the tour will be cancelled shortly after Iceland has their early May reassessment.
