1- Yes it’s true he witnesses our actions
2- Yes it’s true. We have hadiths that state that
3- The Imam witnesses our actions, but it doesn’t mean every second he sees every single thing we do. He is aware of what we do, but we don’t know exactly how. Allah has given him this capacity
4- Doesn’t Satan see us all and know what we do and whisper to us? If Satan has this capacity, wouldn’t Allah’s pure representative have this capacity and more? We don’t say the Imam sees every second and every year. He generally is aware of we do, and Allah gives him that knowledge, so there is no shirk.