Does Viacom own the OT?

[sdp]

Slight Wormquake Spoilers ahead:

We've discussed this a few times before but after watching Wormquake I think it deserves it's own topic. So from what I've browsed on the internet over the years what I understand but might not be necessarily 100% true is that Mirage owned all the designs and almost all if not all characters of the OT. They do not own the actual show and Fredwolf can do what they want with it and they've given the license to Lionsgate for DVD. This was explained even in the old official site about how they could only have synopsis but no pictures of the OT and yet we had the OT turtles in Turtles Forever. However I do remember that there's a piece of "OT" art that is used a lot that is not true OT art, I remember Roseangelo commenting on this once and someone posted maybe this was done to not infringe on the OT designs implying maybe there might've been some legal dispute they preferred to avoid. We also knew that Mirage didn't own the classic theme song.

After Viacom bought the turtles I remember reading an interview about buying the OT I think and they mentioned they were looking at the possibilities or something like that. Now the new show clearly uses a remix of the OT theme song, meaning they licensed or bought the rights for it. Seeing the Michelangelo's OT face didn't mean anything because as said Mirage did own the OT designs. The ending of Wormquake/Manhattan Project clearly had new animation so it doesn't count, however the easter egg of looking through the portal didn't look like the ending, it looked very faithful to the OT and I don't know if it's been discussed but is it a scene from an actual episode with Casey Jones? Seems like it could be. There are only a few Casey Jones episodes so it shouldn't be that hard to check.