There are five Mushrooms left (from the original six). The one Grin hit with his crossbow is looking particularly wilted. There are two additional singed Mushrooms and two untouch Mushrooms.
The two untouched Mushrooms (which were the farthest back) stop moving and attack Ealdwig. Because of their abortive movement, they each only get one attack this Turn. One of the attacks misses, but the other hits! Ealdwig takes one damage and now must make a Save Test or be poisoned! (If you fail the test, you will be at Disadvantage until you make a Save Test.)
The wilted Mushroom makes two attacks on Grin since he is the closest target. One of the two attacks hits and Grin takes one damage and now must make a Save Test or be poisoned! (Works like it does with Ealdwig.)
The other two are still moving. Since they are so slow, their movement takes both of their Actions. Next Turn both Grin and Oliver will be in range for Mushroom attacks unless you move. Yoci was farther back, so she's safe next Turn.
End of Turn 1, Start of Turn 2 and players go first.
Ealdwig is in a 2-on-1 situation and must Save or be at Disadvantage on his rolls until he makes a Save in a following Turn. He can always move away if he needs to keep distance.
Grin and Oliver are now in range for attacks from the three Mushrooms after them. All three of these Mushrooms have damage on them, one more than the rest. Yoci is currently outside their range, but depending on what movement happens, that can change.
Rolls
Yoci Sling Attack DC:5 - Basic - (2d6)
(33) = 6
PM 5 Attack on Ealdwig DC:5 - Basic - (2d6)
(31) = 4
PM 6 Attack on Ealdwig DC:5 - Basic - (2d6)
(46) = 10
PM 2 Attack on Grin DC:5 - Basic - (2d6)
(46) = 10
PM 2 Attack on Grin DC:5 - Basic - (2d6)
(34) = 7