I concur with this.

Exactly, it was fine the way it was.

I only agree with number 3. I think giving Charlie an older sibling would have weighed down the story too much. It's about how Charlie doesn't really like his dad because he's a workaholic and doesn't really know how to relate to Charlie and then it's about Scott becoming Santa Clause and no one believing him. I don't think the movie needed a villain, not every movie does. I think the situations the characters are in generate enough conflict. But #3 is a solid idea. I think if I were that age and one of my classmates stood up with their dad (looking the way Scott did in that scene, before he began to transform into Santa), I would have laughed in his face tbh.

I see there is another post on this forum called "Charlie should've had an Older Brother" where this is discussed a lot in depth. People seem to be evenly split over it there. Also, I recently came across two two fanfiction stories (on Fanfiction.net) regarding this subject. You can check them out here
https://www.fanfiction.net/s/10880836/1/Christmas-With-The-Calvins
https://www.fanfiction.net/s/11636248/1/The-Story-of-Michael-Calvin
I might be in the minority, but personally, I don't think Charlie having an older sibling is a bad idea, especially after reading the above stories. The movie was fine as it is, but I think it would have been an interesting subject to explore. If they ever rebooted the franchise (which I hope to God they don't, but knowing Disney, you never know) they should explore this further.
That's just my two cents.

I don't see any depth or possibilities adding an annoying older sibling. That would have been a nice post to elaborate on.

Consider the daffodil. And while you're doing that I'll be over here looking through your stuff.

I don't think the villain was meant to be Neil, but the fact that people don't believe, so non-belief.
Scott having a second child would have been a little ehh, because the jealousy between the siblings would be a distraction, to me.
They mention that he was bullied after saying that his father was Santa? I don't think so.
I like the fact that he didn't get bullied.
"Do you even remember what you came here to find?"

This is "Christmas" theme film. You don't want this to be too heavy handed. It'smeant for families. They did a great job with this film.

I'm with you.

All of that Woukd have been terrible.