As of now, there aren't any more King Cobra footers remaining. King Cobra has been completely replaced the new ride "Banshee," at Kings Island.
Also, the trains that belong to King Cobra were moved to Kings Dominion in 2009. They are located behind the Flight of Fear ride. The trains can be seen by Google Earth/Maps, trespassing (Highly not recommended,) or looking towards the back of the Flight of Fear as soon as you exit the launch tunnel in the ride, "Volcano the Blast Coaster."
An update on the trains: From what I've noticed from my last visit to Kings Dominion is that the King Cobra trains look like they do not have their set restraints on. (I saw the trains on the Volcano the Blast Coaster, so it was a bit hard to identify every single detail.) Also, when I got to the ride Shockwave, the restraints were either repainted from yellow to black (With a bit of yellow emphasizing the handlebars,) or the old Shockwave restraints were replaced with King Cobra's. This is a theory. Please don't interpret it as a fact. That's about it with the trains. Also, if you don't know what the ride "Shockwave," is, it is a TOGO stand-up rollercoaster. It looks almost like the King Cobra, but without the banked track part. (Tricktrack.) Look it up yourself for more information.
As for SkyRider at Canada's Wonderland... That ride has been removed from the park. It has been relocated to an amusement park called Cavalinno Matto, in Italy. (You could probably tell by the name.) From what I've heard there is no new name for SkyRider, but it doesn't posses the name "SkyRider" anymore. It was either named after the park or it doesn't have a name as of now. (This is fairly new information, correct me if I'm wrong.)