I may be wrong, but from experience,
1.]
While

purified, and one charge left, if hit with

neurotoxin, you lose a point of purify your charges, and still receive neurotoxin card-play-induced poison.
i.e.
1. i have +1 charge of

purify
2. opponent hits me with

neurotoxin
3. i lose my last

purify charge
4. every card i play will make me receive a

neurotoxin charge even though it doesn't display
(probably a visual bug; highly unlikely intended but possible)
2.]

Immaterial creatures don't drown
3.] For clarification,

Cloak resets counter when stolen
4.]

Shard of Patience stops only the first attack of a creature with

adrenalin
5.]

Catapulting a

poisoned creature transfers poison counters to your opponent. (not sure if only a % of the poison counter is transferred)
6.] newly spawned

malignant cells can attack even under the effects of

Shard of Patience, before they gain the +2|+2 bonus