Vacuum I would give a definite yes (you're manipulating air) and since there's no attack roll I'd say the RR is appropriate.
Death Cloud is intended to be like a 'storm cloud' and the damage is caused by the electrostatic charge in it, so yes on being an Elemental Attack Spell. Since you can make a moving maneuver to escape the forming cloud and from there on out you basically control if you're in it or not (unless they've got you cornered - then you're just hosed) I would not give an RR.
I believe both those rulings are consistent with RMSS Spell Law too.