On page 13, if the original line had Callotta's name in it, then it was likely Nell starting the intro followed by a long pause as she thought up the rest. The ? would have been there to indicate Nell's pondering of what she'll say. It's hard to describe in text, but if you can picture those 4 panels going something like how I have it below, it might make sense.
"Um, Callotta-san, this person is (internal monologue)[Now how should I explain him] ? ... ... [AH!] my follower, etc."
This is just my thought on why the original line would have had Callotta's name, but the way you changed it makes perfect sense as well, in fact, it's easier to understand, and an awesome job overall, too. Thank you for your hard work.