The only caveat is with the talent Hit Combo. SEF clones proc their OWN Hit Combo Buff separate from the player. So a player can be at 6 stacks of Hit Combo and the SEF will be at 3 stacks of Hit Combo, and there will be a difference in damage because of that. From what I am hearing this behavior IS intended. I am still in the process of trying to model that behavior into SimC so I cannot say for sure how much it will affect the overall damage. Due to low uptime of SEF and the rampup with damage with SEF, I don't think it will affect it too much but that is just a hypothesis at this point.
So when you pick Whirling Dragon Punch you would use SEF on single target situation like Fel Reaver ground phase or use it only in AoE situation to build up fast SCK stacks?