Just a quick one, if a creature with a deathtouch also has double strike, does it damage the player/walker twice (first strike damage, then regular damage?). If so I presume it would get 2 +1/+1 counters? If that is correct, does Vraska instantly add the counter to the creature, so it would have one more p/t for its regular portion of combat damage, or does it wait until after the first strike and regular damage steps are done? I assume it has to wait, but I was unsure if there's any room between first strike and "normal" combat that triggers like hers could resolve?
In general, a creature with double strike can deal combat damage in two different combat damage steps (C.R. 702.4b, 510.1, 510.2), so that Vraska's first ability will trigger twice if that damage is dealt each time to a player or planeswalker and the creature meets that ability's criteria each time.
However, Vraska's first ability doesn't do anything right away when a creature meeting its criteria deals damage to a player or planeswalker (C.R. 603.2). If that creature leaves the battlefield (whether due to damage or for any other reason) before that ability resolves, the creature won't be there to be given a +1/+1 counter. See also the reminder text of Siegehorn Ceratops and this thread.
Remember that all double strike does is give a combat phase two combat damage steps rather than one (and restrict which creatures assign combat damage during those steps) (C.R. 702.4b). Double strike doesn't mean—
that a creature with that ability assigns twice its power in combat damage (see also this thread), or
that that creature assigns and deals combat damage, then assigns and deals combat damage again, with nothing in between.
Just a quick one, if a creature with a deathtouch also has double strike, does it damage the player/walker twice (first strike damage, then regular damage?). If so I presume it would get 2 +1/+1 counters? If that is correct, does Vraska instantly add the counter to the creature, so it would have one more p/t for its regular portion of combat damage, or does it wait until after the first strike and regular damage steps are done? I assume it has to wait, but I was unsure if there's any room between first strike and "normal" combat that triggers like hers could resolve?
However, Vraska's first ability doesn't do anything right away when a creature meeting its criteria deals damage to a player or planeswalker (C.R. 603.2). If that creature leaves the battlefield (whether due to damage or for any other reason) before that ability resolves, the creature won't be there to be given a +1/+1 counter. See also the reminder text of Siegehorn Ceratops and this thread.
Remember that all double strike does is give a combat phase two combat damage steps rather than one (and restrict which creatures assign combat damage during those steps) (C.R. 702.4b). Double strike doesn't mean—
EDIT (Jun. 17): Correctness edit.