I don't get why Cirno is being chewed out so much. For one, she's technically a kid doing what kids do. When she runs into you, she just has childish confidence. It has nothing to do with her being bright or not. Speaking of which, how was it decided that Wriggle and Mystia are part of "Team 9"? I could understand Rumia and Daiyousei, since they're in the same game and adjacent to eachother by stage order, but why two characters from an entirely different game? I'm not complaining though. It's an interesting grouping, but it's a special case.
And I suppose compared to everyone else in the mansion, Meiling isn't all that threatening, but she is physically strong and her power to manipulate chi isn't something to chortle at. I don't think Remilia would hire a weak gateguard anyway (knowing how prideful she is), so it's obvious Meiling has great worth in her eyes.
About Cirno: My beef with her is mostly about her in-game quotes in eosd, where she threatens to kill both heroines and doesn't have even one portrait where her expression isn't "angry". Of course, Touhou is the game where the fandom feeds canon sometimes, so that by the time of Hisou Tensoku Cirno is much more nice and sociable at her ending.
About Team 9: I read that they are "the childish characters without importance for the plot" and that's explanation enough for me. I suppose that IC, at very least, Cirno knows Daiyousei (or whatever her name actually is), Mystia knows Wriggle because they're kind of neighbors and probably both sparrow and firefly met Rumia during the times they are looking for some delicious night snack (read: people).
now some random shotgunning:
Eirin - wait, she IS a sadist. Not a leather-clad dominatrix sadist, but she clearly enjoys to inflict pain on Udonge. About Eirin in general, i like to think she has a near Dr. Manhattan level of detachement from humanity with the single exception that she's devoted to Kaguya. Really, If not by Kaguya, Eirin would probably be creating life at another galaxy.
Touhou Grimdark - while I still have to READ fics with this theme, it's not repulsive for me if it makes sense. Of course, you have to separate the grim from the dark: Gensokyo IS a dark place. There are people being eaten there, probably every night. It's not a grim place, however, or at least the stories shouldn't be told about this point of view. In this, I believe Gensokyo should look a lot like, say, Diskworld, where many times the comedy is only in the way the author describes the cruel and unusual situatons the characters find themselves into.
Yuuka - is a classic psychopath. A polite, funny and pretty psychopath, that thankfully for the rest of Gensokyo is usually more into flowers than people (think an unholy cross of The Joker with Poison Ivy). There's not other way to join her portrait in PMiSS with her quotes in PoFV: She enjoys tormenting people and youkai alike, never shows a drop of empathy and Akyu wouldn't be lying about her abysmally low level of human friendliness, would she?
Alice, Marisa and Patchouli - one thing fanon almost never catch is that magicians are the nerds of fantasy: studious, haughty, obsessive and quirky people. They are more intelligent than almost everybody else and are storehouses of knowledge (but mostly useless trivia). Both Alice and Patchouli like to showcase that, while Marisa keeps to herself, just to let out one phrase or another that shows how much she does know.