I actually rewatched that interview, and Tameem says that his company is "working closely" with Capcom on the gameplay, and Alex Jones said the same thing about the bosses because bosses were "Capcom's specialty."
So, I guess that could either mean Capcom has full hands-on or they are closely supervising the gameplay. But, you know, from what I gather so far, Ninja Theory has boasted more about art direction and what they believe is today's culture than the thing that actually defines Devil May Cry: being innovated.
I wouldn't be surprised if Capcom developers are more involved in this project than we think.