I think the more restrained Ren fits there, because that sort of rage beneath the surface seems more dangerous and already has a viewer wondering in the back of their mind, what’s he going to do when he really lashes out?
As far as the black comedy, it can work even with the context of the villains (what does one call the “apology accepted Captain Needa” scene from ESB if not calling for very dark laughs?), its just a little riskier in an opening because you don’t want the audience too comfortable in associating that tone with the antagonists unless its a consistent element.
With the First Order and their presence as a threat, I think the visual and symbolic shorthand is really potentially effective tool in demonstrating that. I’ve mentioned the example in ESB, but ANH as well paints the picture of what the Empire is with just with the Star Destroyer engulfing the Tantive IV and Vader surveying the dead Rebels on board.
The image you suggested in the opening crawl could be the key to selling why the Snoke’s forces are dangerous right now. Maybe we see images of the New Republic now scrambling to maintain order and the Resistance struggling with supplies and coordination (perhaps via surveillance/security video Hux and company are watching if you still want a villain opening) and then we cut to the First Order and it is organized, it is well maintained, and it is disciplined. One overt visual contrast and we immediately know that in a sea of galactic chaos, this is the group that is still in deadly control of itself. They lost their base/weapon, and not only haven’t they not fallen they’re still running like clockwork.
Finally as it pertains to Snoke, I don’t know your full story; it feels like there should be some kind of intrigue to his order of taking out Luke. Perhaps its something involving Rey or some weakness of Skywalker’s Snoke thinks he knows, but “evil overlord ordering destruction of one of the heroes” is such a standard scene in fiction like Star Wars that one kind of needs to have some sort of pizzazz or hook to keep the audience fully interested.