Oryx is op

Me because I killed them all

Skolas's two main weapons would be ineffective against either of them, as he cannot taint your light if you do not have light to start with, and his scorch cannon wouldn't hurt crota and Atheon it would barely scratch without times vengeance, which as a non guardian he wouldn't get. The mines wouldn't come into play as we are led to believe they are from variks in order to try the guardians rather than something skolas controls. Crota could defeat skolas by just melee, and his melee is more powerful than skolas would be assuming he used his silent fang to get him a sword to use. (One hit kill vs sometimes a one hit kill). Further once Crota shot any drug or shank in the area he would summon oversoul so skolas would have to shoot it, and as we know explosives aren't as effective against the oversoul as bullets, so his Cannon wouldn't stop it. The Crota atheon fight would be more interesting. Part of me envisions atheon allowing Crota to swing at him, then changing his own placement to be away from the sword shooting at it, and changing Crotas position to be hit by his own sword upon impact, leading to the iconic "stop hitting yourself" moment and thus defeating Crota This does not reflect which boss I feel is hardest to kill. The mechanics of guardians and bosses fighting is different. Crota is by far the easiest

Randall the vandal

Crota is a god atheon can send you through time skolas just shoots a scorch cannon Atheon because controls time and he rapid fires a torch cannon

Skolas. He would just poison them and they would die after 30 seconds lol

Crota ... I think the Vex are tools or creations of the Hive. Skolas is just a damage sponge with no special powers whatsoever. Crota could probably just one shot him with the sword and be done.

Skolas would win because Crota and atheon would get disconnected

To use logic on this.....[spoiler]atheon would win by a landslide because the only time to damage him is time something and skolas and Crota can't get out so they are forever lost in space and time[/spoiler]