Either way, you get an attack trigger, not a combat damage trigger, so even if you lose Locke its not the end of the world if you were just digging for some treasure
Of course, other versions of the effect can't be nullified by combat damage but it's much harder to sneak through opposing defenses when you can't Swords to Plowshares prominent blockers
As that ability resolves, if the creature has a +1/+1 counter on it for any reason, you simply won't put any +1/+1 counters on it
Archetype staples are fine, but color or generic ones arent going to be mentioned here
(They each put the top card of their library into their graveyard.) If you are instructed to put a card into your graveyard from your library without using the word "mill," (by the effect of Rowan's Grim Search from Wilds of Eldraine , for example), Raul's first ability won't allow you to cast it
This card plays great alongside Rod, letting you stack multiple pings per spell