AFAIK any sucessful damageing attack will reveil a stalker, the slow it's self will not, the vines / immoblise should if they can hit.
However I doubt that a stalker will stay put long enough for them to spawn / effect
Question: Does chilling embrace break hide? if so then the slow effect should too, however it's almost impossible to tell where the patch is at any given time if there are no vines out.
Note: On further testing the vines only spawn within the AoE of the slow patch at it current given location, Vines can be knocked back but they then respawn within the slow patch (which cannot be knocked back)
Mob's will also target the patch it's self although it is untargetable by you and I suspect it has No hp (while the vines do)
btw chilling embrace doesnt unterupt ASes anymore now it need to be damage to do that/break hide.
Gin
I'm fairly sure Creepers doesn't reveal invisible foes or break a Stalker's Hide, whether vines appear I'm not sure. I do know that Arctic Air from Ice Control will reveal a Stalker. This is one of my problems with Warburg, I've almost no capability Vs. Stalkers so hardly ever go there.