I've heard that IA's height hasn't given
Is that real?
Very much real, most Vocaloids have little details about them.
People tend to presume because the Crypton lot have everything every other vocaloid will have it too, but the case is most don't.
Her weight and age aren't given either while I'm at it.
I love how the fandom sometimes worries about this kind of things lol
I still would love more detailed characters tbh
The most detailed characters at this point are the Chinese characters with Luo Tianyi and co (with the exception of Yanhe who was created at the spur of the moment for them), Iroha (since she was a game character before Vocaloid), plus Azuki/Matcha. The rest either have no details or bare minimum.
I prefer it with a lack of details as it can be binding... Saying that, Lapis and Merli are rarely referenced as fairies and their powers of voice are referenced less.