No they don't, regarding the first question
There is already an observant more or less developed within us, that allows the possession, and detachment eventually
Regarding the second, it isn't really as method acting involves the whole body, the whole body and mind are possessed, so feelings too, not just channelling information you know
The whole body is possessed
I am very good at method acting, but haven't done any yet :))) maybe I am not that good :)))))) ?