Sure, you're more than welcome to use them as reference as long as they're not being copied directly. I have no problem with that. Though if I may suggest, it may be even better for you if you can find some video reference of some real lions and use that. That's what I did for this animation. In fact, I have a little YouTube playlist I put together at the time you could check out: www.youtube.com/playlist?list=…
Now the nitpicks: 1.Trace the position of each paw from all the drawings onto a single layer. Try to draw a smooth line through each of the leg cycles. This with help reveal "bumpy" arcs and uneven movement along the ground.
2.Figure out your fore-paws construction a bit better - or at least decide on a single paw size that works for 'in the air' and 'on the ground'.
3. I like it better if I could feel a solid rib cage under there.