I pretty much agree with all of this. I don't think Khan has the power to stop Mitchell late tho, but he might overwhelm him early for a British ref stoppageKhan would still beat both IMO. Burns is great at controlling fights from his range but I think he'd get picked off by Khan's speed (this is a fight where Amir's speed would actually be key). I'm not sure Khan would be able to stop Burns but do think that he'd widely outpoint him over 12.
I think Mitchell could cause problems if he gets his timing right but I'd favour Khan to break him down and maybe stop him late if Amir was anywhere near on form.