As Top Gun mentioned, Ghost in the Shell and Ghost in the Shell 2: Innocence are not related to Stand Alone Complex.
Mamoru Oshii decided to take his artistic directions to portray certain parts of the original manga for the two movies. Unless you've read all the manga, it will get confusing. Especially for Innocence. Richard Epcar - Batou's voice actor- was in charge of the ADR directing and localization of the dub of that movie, and he thinks that it's just a complete mess. It's confusing and tries to condense way too much into way too little..
But I digress.
Solid State Society is the only movie directly related to Stand Alone Complex, and it takes place after the two seasons.
You don't NEED to see the Mamoru Oshii movies in order to understand what happens in the anime series.
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"A SMARTER hitman would have shot first..." - Major Motoko Kusanagi