Perry Como, pictured with five friends — 4 muppets plus Julie Andrews. Thus, “Como And Five Amigos”.
Clue #2: The first name of the man in the picture is Perry, and he was a famous singer in his day - Self-explanatory.
Clue #3: The number of people and characters surrounding Perry is part of the song title modification - Explained above.
Clue #4: @Deadeye21‘s guess was the closest so far. Also, the altered song title has one more word than the original song title, and words from two different languages. - @Deadeye21 had guessed “Perry Como Estais Amigos”, which doesn’t really make sense grammatically, but it was the right length, had two of the words right, and correctly identified the man. “Como” and “Amigos” are Spanish words, “And” and “Five” are English words, thus two different languages.
Clue #5: Two of the words in @Deadeye21‘s guess were correct. The other two words in the altered song title are in English. - Explained above.
Clue #7: "Como And ____ Amigos". This is now enough information to directly deduce the answer, so no more excuses! - This clue, plus clues #1 and #3 were enough to deduce “five”, but some people need their eyesight checked!
Clue #8: What’s greater than four and less than six (seis)??!! - Dear god, I hope this one is self-explanatory!