Caution: Do NOT use iSpot to identify fungi to eat!
Some fungi are very poisonous so a mistaken ID could have serious consequences.
No interactions present.
Not in my vice-county!
I fear you are right, though there are other causes of Ash die-back.
Several trees looked "poorly" I'm affraid! I have reported it (with photo).
Gardening for Wildlife
There are some ash trees with nice lichens in Wigtownshire.
Lat/Lng: 54.7941, -4.3576
OS grid ref: NX485469