[trebleshot]

No, Storm Shadow was beat down pretty good but fell into the Artic waters before he was actually "killed". He was instead assumed dead since there was no body to be found. It's a stretch, but theoretically the ice water could have kept him from dying by basically putting him into a cryogenic state until CC or some other Cobra goon scooped him up.

In this continuity CC is a doctor, after all.

As for Duke, the trailer does not explicitly show him getting killed. It's mostly fan speculation due to the Rock's lines about "we're all that's left". Duke could just be put into a coma, like in the G.I.Joe animated movie.