If you're right then I think Yano and Senji are officially in-house artists now because official jp twitter account never gave link to their in-house artists twitter account(if they have) like kishiyo, saru, kaede in character announcment post unless they're guest or collaboration artists like ooyari, momi., komeshiro kasu, senji back when I-26 was first announced and the same for yano's forbin and le mars.
I'm pretty sure Yano Mitsuki is still freelance (or better yet she's the in-house artist of Eushully since most of their games literally has her art) and Senji still works with yuzu-soft (according to vndb senji is the head of yuzu-soft) unless he left and went freelance... which might explain why Yuzu-soft's recent titles has been... lackluster for the lack of a better term
or I'm just assuming Yostar already thinks since they are technically high profile artists it should be a common knowledge thing which I admit I knew the art for I-25 feels familiar but just couldnt pinpoint who
or like saying Sayori is now hired by yo-star because of the mobage nekoparaiten
Well it just my thought and curiosity, I noticed it is strange that the Official JP twitter account didn't link to Yano and Senji account in their respective new characters announcement post like they always did for any other freelance artists new characters unless they're in-house artists or just new skins. So that's why I kinda assumed that maybe Yostar, Manju and Yongshi somehow finally got both of them on their side officially.
Oh! I went to JP official twitter account again and check, they did link to yano and senji account in a follow up tweet to each of their respective characters posts. So they're still freelance artists afterall.