you can never be sure, but i personally don't think ridley is going to be a stage hazard at all. not other m ridley, not a clone ridley, neither ridley if he isn't selected ( and is if he is, fiery jeff takes his place )
heck, the i don't know why people even came up with the whole stage hazard thing; '' an enemy from samus's past may appear any second'' doesn't mean ''an enemy from samus's past may appear any second as a stage hazard masahiro sakurai everybody''
sakurai's quote was so obscure, it could mean anything. sure it could mean mother brain, who has appeared. it could also mean lava, sure what the hell i might have died more times in metroid because of lava than of enemies. it could also mean he was referring to the events of other m, that in the pyrosphere in other m, ridley could appear any second.
but i personally still thinks it means ridley could appear any second, playable. i mean there's been so much build up now. sakurai knows what he's doing, he also knew what he was doing with little mac; the boxing arena, it was right before our eyes the whole time. he also knows people want ridley playable, that's why he hasn't given him away yet, or is going to any time soon i think.
ridley playable in smash has always been a thing, and if it's going to ( finally ) happen this time; it's going to be huge. i expect them to reveal him at e3 2014, not earlier.