Poison potency question

Hi I am trying out a mite/arachnalisk build and had a question about poison potency and what its doing. So I have the mite plaguespreader and its perk is “The potency of the enemies’ Poison and Burn debuffs are shared with each other but reduced by 65%.”. and mite skirmisher “After this creature attacks, it increases the potency of the target’s Poison and Burn debuffs by 50%.” So with this information I’m mind here are my questions

1: Once my skirmisher attacks one enemy the potency for the creature will go up by 50% but for all the other creatures it will go up by 17.5% as that is 35% of 50. Or is it just 17.5% across the board? IE if 6 enemy creatures are poisoned, I attack one with skirmisher will the target go up by 50% and everyone else 17.5% or just everyone gets 17.5% more potency.

2: Once the main creature I attacked to increase the potency dies does the potency reduce for the other creatures or will all the other enemies still keep the increased potency? In other words lets say I’ve stacked 400% potency on one creature, so 35% of 400 is 140. So if i kill the stacked up creature with 400% potency, will the other enemies lose the 140% potency?

3: If i have increased the potency of a creature by a lot and then it summons new creatures, can I then poison those new creatures and have the previously accumulated potency stack on to them as well? So lets use the zombie horde boss fight as an example. I stack up a whole bunch of potency on the first 6 creatures but once they die, new ones come in. If i poison the new ones while some of the previously poisoned are left behind, will they share the potency stacks?

Thanks so much for any and all help!