Well since it doesn't look like there's another set of tweets for now, I'll just translate those.
Takahashi seems to realize that continuously introducing one designer after another in the tweets can be rather boring, but he asks that fans bear with him because he wants to introduce as many of these artists as possible. (duckroll note: It seems that the idea of posting some artwork from the game to make it less boring has not dawned upon him, unless he's not allowed?
)
Today he introduces another two artists involved in the project - Fumihiro Katagai and
RARE Engine.
He also shares that as development on the game progresses, they're seeing a lot of stuff where they go "wow, this is even more interesting than that." He feels that when a project has reached a point where the general direction has already been set, it can be pretty challenging for those joining after. He is very grateful to those who happily accepted the offer to take part.
Takahashi doesn't talk about what the two designers are working on. I can give some background on them though. Katagai is a mecha/conceptual designer who works on anime. He did some guest mecha designs for an episode of Space Dandy, and he worked on various stuff in the past like Last Exile, Votoms, Eureka Seven AO, the Short Peace segment Farewell to Arms, etc. I'm not familiar with RARE ENGINE's work, but he's an illustrator who seems to work mostly on magazine illustrations and artwork for digital card games like Code of Joker and Lord of Vermilion.
Edit: Katagai previously tweeted some of his mecha design work from Gyrozetter, should give an idea of his style:
