That must have been one heckuva cat!!Those liners will not provide a "seal" of any kind - they are merely "splash guards".
While the plastic push-pins will not be "snug" they will be secure. They won't pull out unless the center pin is pulled out first. Now that I think of it, had mine been secured with the push pins instead of screws that cat I hit a few years back probably wouldn't have done $2,800.00 worth of damage . . .