Subaru is now claiming credit for most of the project now. Of course, like everything in life, the truth probably lies somewhere in the middle.
As Toyota IS campaigning the car under their Gazoo Racing banner at the Nuerburgring VLN, so my guess is that Subaru did most of the powertrain, Toyota did the styling (confirmed by Subaru), wrote checks, and tweaked the suspension.
I actually appreciate all the leaks. Now I know that I'll take a Toyota FT-whatever in grey metallic with the stick and red/black Modellista interior and swap out the rear lights for Subaru bits.
I'm dropping out to create a company that starts with motorcycles, then cars, and forty years later signs a legendary Brazilian driver who has a public and expensive feud with his French teammate.