Well, I can see this for a few reasons. First, Toyota owns a good portion of Subaru now. Second, subaru and Toyota are already sharing production facilities. One being the plant in Indiana, which makes the Legacy, Outback, Tribeca, and Camry, and it's possible this car is based on the Legacy platform.
The big reason why I can see this is the shape of the car. There's very little hood length. For a RWD car you want a longitudinal drivetrain, not transverse. An H4 is a considerably shorter engine in that arrangement than an I4 would be.
But whatever the engine, if Toyota delivers a 2500lb RWD car for around 17K it'll fill an empty niche and probably sell really well, *especially* if they put a white AE86 in the commercials.
There's been articles about a small RWD Subaru sports car, other articles about the Subaru/Toyota joint car, and articles about Toyota working on an AE86 sucessor. There's *something* coming in the next couple years from Toybaru. Whatever it is, I think it'll be worth a close look.