Hopefully, you can see that the mesh around his pelvis gets deformed. The ankle also squeezes in, If you have any idea why this is happening or how I could fix it I would greatly appreciate it.
Might want to check the weighting. Click on the option to change from Object Mode to Weight Paint Mode. Try and use the brushes to adjust the weights applied to each area.
Make sure your bones aren’t posed or that they don’t have some constraint dragging them out of their normal rest position in pose mode. If that doesn’t work, post your .blend file so we don’t have to use a crystal ball to divine the problem.
It does, but only because the leg IK constraint pole angle is wrong, causing the legs to rotate 180.
After parenting with auto weights, select a leg bone with an IK bone constraint in pose mode.
Then go to Properties > Bone Constraints, change the Pole Angle for the pole targets, about 180*.
This should correct the problem.