6Ac Definition = TIPPLE . If you remember the old advertising slogan for milk "Drink a P_ _ _ _ milk a day", then move a one letter word for before from right to left
16D is jumbled. Definition = volcanic opening. I looked up fumarole in Bradford's. Sailors is an abbreviation for their service, usual one letter abbreviation for island, include in a HOT + O(f)
25D Not jumbled. Def = old actor. Empty g(az)e and put the two remaining letters in a 4 letter word for brilliant that might be used to describe a performer.