Current tag is toyoomi_hideyoshino. "Toyoomi" should actually be "Toyotomi". In the first episode of the anime she is credited ヒデヨシ(日出佳乃), though looking at it could be full "civilian name" (so, hide_yoshino?) The second episode drops the stuff in parentheses. It seems like it could be an anime-only thing, so maybe the best tag would be toyotomi_hideyoshi_(sengoku_otome) to keep her consistent with the others (even though it's longer with a qualifier). Could alias hide_yoshino to it, maybe...
Going by post #894698, the artist tagged it as 豊臣ヒデヨシ on Pixiv, which matches the Japanese wiki page. 臣 can be read either "omi" or "tomi", so - having not seen the anime myself - I'm not at all certain which it should be. Her name is most certainly Hideyoshi, though.
sgcdonmai said: 臣 can be read either "omi" or "tomi", so - having not seen the anime myself
Well, the actual person her name is based on has his name read "tomi". It is said in the anime, I'm pretty sure, though I'll have to double-check as I wasn't paying close enough attention. EDIT: I think she's not really referred to as "Toyotomi" (at the start of the anime at least, it's not part of her name, just "Hideyoshi" as a nickname), but the historical person is brought up and pronounced like that. The official websites for the anime do list her with the family name Toyotomi included as well as mentioning real name and nickname.
日出佳乃 looks like a full name (Hide Yoshino), not one big given name. Crunchyroll subtitled it as "Hideyoshino" but I think that was a mistake, as it doesn't make much sense. Her teacher called her "Hide-san", and I believe it's standard for teachers to refer to their students as (family name)-san.
And yes, her name in the anime is hide_yoshino. In the game it was just toyotomi_hideyoshi I believe. I'm inclined to go with hide_yoshino, which I've done for now.