Hi,
1. It seems to be a bug. Change the code:
if($element->vote_id == '0' || $addVote){
to:
if(($element->vote_id == '0' && isset($oldElement->vote_published) && $element->vote_published == '1') || $addVote){
in the file administrator/components/com_hikashop/classes/vote.php and that should fix the problem as it should count the vote only on the confirmation from your end.
2. There is no way to change that date from the interface. It would require some development. Or you could directly change the date in the table hikashop_vote in the column vote_created
3. There is no option for that. That would also require some development.