Now that I've gotten all the secrets I can finaly answer this question.
In principal no. You do not need to revisit mission to get all the secrets. You just need keen eyes as you go through the levels. Most secrets require just some platforming to get to, but some also require hitting certain switches or pulling levers. Latter of these tend to be hidden.
The later mission start to have numerouns points of no return that do prevent you from going back to earlier parts of the map. These can pervent you from getting to some of the secrets you missed earlier.
Also, the double jump you get in the 5th mission, the Argent Tower, makes traversin the earlier maps less of a pain, so it's easier to get the secrets you missed.