If you start 11,16 with two cats, there's a different solution (that involves sacrificing one cat to reposition a medusa early on) that will let you take your remaining original cat and both revived cats through the top exit.
And while 9,17 will get you the spare cat you need, it's only a shortcut to do so after it's opened. Without that shortcut (and in order to open the shortcut if I remember), the extra cat is part of a loooong path starting at 9,14.
If you've opened any of the other shortcut portals into the path then you can skip parts using portals at 7,16, 6,17, or 9,19. Otherwise you have to take the long way around (and you'll open those portals as you go).
Oooh, and actually for 10,11, I might know why you're stuck now. How did you get there? We might have gotten there from different paths, which is why I had enough movement. You need to teleport into the level - not using the map teleport - in order to start on the 9-step flag in the upper corner to reach the door. You'll find what you need to finish the room up there.
That's not really a surprise. The solution is very roundabout as you need to move the final flag closer to the exit in order to get out with both cats. So you've got some boulder pushing to do. I don't remember the steps, but I believe you need to move the second-last flag a bit in order to have enough room to get the cats in position to be able to push the last flag.
