1 - Can't say anything about Han not working against Land of Lightning Treasure Rares/Supers.

2 - Plunder is not limited to once per day. If you plunder a S or A rank convoy you have the chance in getting a ticket that lets you plunder a 2nd SS. Same with Convoy if you do a S convoy or A Convoy.

3 - Hidan at this point won't be fixed. Best to bring CC and a ninja that prevents a resurrect on ninjas like Onoki/Mabui and make sure their mysteries kill them.

4 - Initiative never lead to higher damage, it only affects who moves first.