There is a board/case, Dexter Industries BrickPi3 which allows a Raspberry Pi 3 to work with Lego Mindstorms. This doesn’t include any Lego parts, just the case, the RP3, and other things to get this to work. The interface board included with this allows Lego motors and sensors to be used.
I know that ROS will work on the RP3. It isn’t the best platform for it, but it does work.
Jay