The reason why cocooned victims likely remember is that they have not been sedated at all, Verheiden was cocooned and conscious while having a hugger on him, it is possible a facehugger won't sedate cocooned victims because it is unnecessary, the hosts can't escape or fight back.
I think they can fight back. They can shake their head. Force their mouths closed before penetration. They can bite down on the facehugger if penetrated, and if wounding it, unbeknownst to the host, release acid blood and kill the host. I think I'd try anything to fight the situation.
But since the facehugger is going to die anyway, it has absolutely no reason, no reason at all, not to sedate the host.