Only the particulars have changed - the form is identical. I am sorry, but validity is a formal quality of deductive logic. If your syllogism is valid, then my syllogism of identical form must be valid. And if mine is invalid, then your syllogism of identical form must be invalid.
Unfortunately, what you have done is taken a conditional statement of the form "if x, then y,", or more formally, x implies y, and from it inferred that y implies x. Needless to say, this does not follow. This is not a straw man argument, I am sorry to say.
What I am doing in the major premise is combining two separate propositions, neither of which are conditional upon the other. The first is that there are no other possible causes for resurrection other than God. The second is saying that in addition to the first proposition, in order to be able to cause resurrection, God must exist. It logically follows from the fact of the resurrection, that God exists.
Thus, as Dimensio put it, the major premise combines these two thoughts and the syllogism is in the form of: If and only if X, then Y. Y. Therefore X.