Nein, Dandelai is the tall one as M4 named her as such in chapter 12, her name is a play on Dandelions, Anna is the child. Specifically a prototype Nyto known as "Larvae" which possess a digimind despite being human. We first meet her in Chapter 4 of Polarized Light and she refers to herself as "Anna" (Also the Nyto whose clothes has 01 on it is her, the other Larvae dont have any distinct names)
Nein... Ahem, dont hover if you truly do not care. I'm not fond of spoiling stuff, but i'll still answer your question.
her name isn't "Larvae" the prototypes themselves are known as Larvae, Anna gave herself a name, probably influenced by Ange. Anna's code name is EOT-1 and they're essentially young Nytos who've not become "Nyto". Dandelai is essentially M4's OGAS protocol which assimilated into one of the indifferent Isomers during Shattered Connexion, said body originally belonging to Nimogen (Hence the black/gold dress) as the indifferent Isomer pretty much fried Nimogen's digimind and assimilated it into their own, before M4's OGAS did the same to it. As for UMP40, she's been dead since Operation butterfly, and still is, the UMP40 which resides in UMP45's digimind is nothing more then a fake created by UMP45's own OGAS protocol which has been locked away deep within her digimind, although hers is significantly weaker the M4s. For the record, the game tells you that UMP40 in UMP45's digimind isn't real in her MOD3 stories.