No, he could jump. just not jump-attack which is what sliding dash does.
(Like when you approach and enemy and you automatically jump to reach it.)
Not really. it's the same case as Ven's...
Ven's model was in fighting position.
Antisora's model was in fighting position.
It's the same thing like the anti-saix and Anti-riku hacks that were in days.
While the model looks a-like it doesn't have the required animations and will be hell too buggy. (an Arm in your head, hello.)