Extracurricular Activity -- Skeet Shooting Club Solution

When you attempt to solve this puzzle, you quickly discover that the words don't match the clues. None of them are an anagram of a planet, and "pluralized by adding three letters" suggests "child" but what's there instead is CHILL. You have to change one letter in each word to make them work. That's the "other thing" you were supposed to figure out.

Which word:
anagrams to the name of a planet? HEARD -> HEART (EARTH)
appears elsewhere in these questions? PLANES -> PLANET
becomes a new word when you remove both T's? LESTER -> LETTER (LEER)
becomes its own synonym if you drop its first and fifth letters? EVALUATE -> EVACUATE (VACATE)
becomes the name of a fish if you swap the letters on its ends? PUNT -> AUNT (TUNA)
changes gender by having SS added to the end? PRANCE -> PRINCE (PRINCESS)
contains three pairs of double letters? COMMITTED -> COMMITTEE
forms new words upon removing its first, second, or both first and second letters? SLAKE -> SLATE (LATE, SATE, ATE)
has been a name in the news of late? MUDDY -> BUDDY (Errata: the "name in the news" is not the name of a human being)
has the same cryptographic pattern as FLOODED? COLLAGE -> COLLEGE
is a first name of a famous director with the same cryptographic pattern as the director's last name? WORDY -> WOODY (ALLEN)
is also the name of a fictional rat? SPLITTER -> SPLINTER
is a name sounding like a famous film monster? ROBIN -> RODIN (RODAN)
is Pig Latin for a name meaning "king"? PRAY -> XRAY (REX)
is pluralized by adding three letters? CHILL -> CHILD (CHILDREN)
is the name of a cable channel? BRAVE -> BRAVO
is transformed to a new word when its first letter is changed to a D and moved to the end? SALOON -> SALMON (ALMOND)
sounds like a word meaning "gospel" when pronounced with a lisp? TRACE -> TRUCE (TRUTH)
spells a word meaning "jelly" if its last letter is moved to the front? PLATING -> ELATING (GELATIN)
uses all the letters that appear in the last seven words of a popular Christmas song? DEPORTING -> DEPARTING (AND A PARTRIDGE IN A PEAR TREE)

The changed letters aren't used. But the leftover words are CONCERT DO MOUSE RODE. Keeping them in this order but changing a letter in each one gives the final answer, CONVERT TO MORSE CODE.