Transformers Toy Rumours (must note a source)

[griffin]

A number of those have been in recent "leaks" and "rumour" posts, so hopefully that means they are more likely to be real, and not just different people recycling the same rumours.

The Studio Series Sentinel Prime and Scrapper are definitely coming. Scrapper was the name on the Devastator promo pics early last year, and Sentinel Prime was on a Japanese product listing a few months back, we just didn't know what size class it would be (they do their Studio Series in a different number order).
Blitzwing may have been rumoured before, but if not, it would be expected as one of the few featured robot characters in the Bumblebee Movie (and would have needed a couple of years to design properly, unlike the toys released during the movie that get rushed in order to be in stores in half the time).

Skipjack should just be a yellow redeco of Rampage... as it was the original colour of the Constructicon that Bumblebee fights in the ruins after destroying Ravage (you can see the yellow on the bulldozer and a very rushed two-dimensional red recolouring, as a yellow bulldozer would have been filmed, but I think the robot mode had to be changed to red so that it was easier to track the fist-fight between Rampage and Bumblebee - and I'm pretty sure that the advance screening of some scenes we saw at BotCon 2009 before the movie was released, had a yellow Rampage, which would explain the rush job on the red bulldozer, as the animated robot mode could have its colour changed very quickly in post production)
Having a yellow Rampage released will allow fans to create a screen accurate Devastator with a yellow leg instead of red... and most of the Devastator toys for ROTF had a yellow leg or yellow Rampage. My guess is that the Studio Series Devastator already had 3 yellow Constructicons, so it was decided that it would look better having the red Rampage that Bumblebee killed, to add a bit more colour to the team and combiner, even though it is not screen accurate.