So, if you roll that the hindering terrain on the Krakoa map is blocking terrain and someone blows up the square of blocking terrain, does the debris from the destroyed blocking terrain go away after the turn is over and the square reverts to hindering?

If it doesn't go away, will that square be considered destroyed blocking terrain if the roll goes off again?

I see this as potential Magneto abuse territory.

I would think they go away. Debris tokens from destroyed Barriers go away, after all...

Also, on the roll of 6 it makes an attack that ignores hindering. I don't remember if it is a fig, feat, or BFC, but I know something in the game specifically mentions "ignores hindering terrain and the effects of characters in hindering" or some such thing.

So if I am stealth and in or behind hindering when this attack is made, can I be targeted?

A lot of effects in the game ignore hindering terrain.

You can since the LOF ignores hindering terrain. Without hindering terrain, there is nothing to activate the Stealth.

Has there been any ruling on what happens to objects on hindering terrain when Shifting Foliage is rolled? If they would be destroyed, what about Mjolnir? What about special markers like Trigon's Dopplegangers?

My vote would be nothing happens. It is not blocking terrain...."Printed hindering terrain acts as blocking terrain instead until the beginning of your next turn."

Another question that we had come up with Krakoa: What do you do if Krakoa attacks, but his only valid target is in an adjacent square? Can he still attack that target?

What he said. It only effects the printed terrain.

By the way this map schooled me last night....My Golden age Excalibur team were beaten down when I kept rolling 4 at the end on my turn....

he is not a character and would not be subject to the rules of Ranged attacks and Adjacency.

BTW - Here is the wording I was thinking. It's from SI Dr. Strange: "Dr. Strange ignores the effects of characters and hindering terrain (including team abilities that give hindering terrain bonuses)."

My thinking was that they specifically mention the hindering bonuses but then omit it from Krakoa leading me and another player wondering if Stealth did indeed still matter.