your conclusion is inaccurate again. yes the shaman created a storm magicialy but its essence once made was that of a regular storm. it wasn't a sentient storm or anything that operated unnaturally. so she should have and was able to control it as she would any naturally occurring storm.
Well keep in mind the magical/divine blast she used against adversary was effective because natural means of attacking him won't work. Which is why Roma use of magic and the spirit spell was the only way the xmen were initially able fo bear him. Im not sure if a divine blast would hurt Vulcan but I would argue she wouldn't need to even go that route as Vulcan even fully powered is still just a human.