It's entirely possible, from what I have heard from your boys Hex is one of the most inteligent dogs I have come across. The sex toys could definately be him, if he has plenty of toys he could see objects like that as his toys too and putting them between someones legs while they sleep could be his way of saying "play with me when you wake up". Plates are a dog's best friend - if they disappear when dirty and reappear somewhat cleaner hidden in places like beds then it's almost certainly him. Dogs often attempt to "hide the evidence" (at least my boys have lol) so in someones bed or under a cushion is ideal because in their minds they have just burried it.
As for locked doors... while it is possible if they are locked using keys or something small it's a little unlikely a rottweiler would be able to manipulate something that small. The same with the shampoo - it would taste good to him, the only possibility there is he played with the bottle and the top came off but that would have left a mess he wouldn't have been able to clear up.
__________________
|