Nasus, Pantheon and some items

Hey all, just have a few questions about a few items and abilities.. So first off, I can't really find anything useful online in regards to the questions I'm asking, have haven't had the time to take off and test these for myself, so if anyone has any information regarding this, would be much appreciated, thank you :)

So initially, my first question regards Nasus, I'm interested to know when a Titanic Hydra is built on a Nasus, when he utilises his q to last hit a minion, and in the process, the passive of the Hydra also takes out the remainders of the minion wave. Do all the minions killed count as stacks since Nasus's q was being used when they were all killed or, does it only stack the minion that Nasus q'd individually, regardless of how many minions the Hydra active kills?

Also the second question is regarding Pantheon and Rageblade I was wondering if Pantheons passive counted as an 'on hit' effect, meaning that Rageblade would then enable him to 'at guinsoo's rage' be able to have his passive up every second auto attack? |'ve heard that this was possible, but I doubted it, and tried to find it online; however turned up empty handed. Thank you :)