Only if you intend to fight it. Right now I’d say you, like the rest of the party, haven’t been noticed butt you should roll a stealth if you’re going to do anything more complex than moving around, and even then that might need a Roll too.
@rush99999 Moving around the rooftop you're at you should be fine so long as you're not doing anything too obvious, however if you're moving to a different ruin then yes, with a new acrobatics or athletics since you're trying to preform this maneuver with more difficulty than before.
As for the cyclopse's distance, you're currently thirty feet above the ground and the cyclopes is crouched near the ground making him roughly twenty feet tall, however he would be taller if he stood up. So from the edge of the rooftop to the top of the cyclopes is about ten feet give or take.
None that you can access via roof hopping. Only the orc's hideout and the immediate buildings next to the ruins you're on will give you the benefit of highground/cover, and that's within 30 feet. Anything further than that and you'll have to climb down the ruins and at best hide behind a corner. But even that's only going to be about 40 feet away.
Before I confirm anything, I just want to let you know that you are committing to these rolls: I fully expect you to be using them immediately, not holding your rolls until the situation changes or for your to discuss with the rest of your party. Because once I give you an answer I can guarantee you that it will start combat immediately before anyone else will get to react. With that in mind, will you still continue to act?
I've already made the necessary rolls. And while I might have rolled a 12 on one the other two were both 22s. If you think you could do better feel free to have Roy offer to run the distraction in Angus' stead. If not, have him find somewhere to hide and kick back until the cyclopes is sufficiently distracted.