So I have heard mixed opinions of how this works and just want to clarify.

If you fly over a rock, can you still perform the evade action as you fully complete the 3 - 5 speed maneuver?

Yeah, flying over an Asteroid just makes you skip your Perform Action step and full throttle happens before then.

If you went over a Debris Field and stressed yourself you wouldn't be able to obviously.

Yes, getting on an obstacle skips your perform action step, but does not impede to take more actions from another sources.

1 hour ago, Arachneo said:

Yes, getting on an obstacle skips your perform action step, but does not impede to take more actions from another sources.

Small point, landing on or flying through an Asteroid skips your perform action step. That's specific to asteroids not obstacles in general.

Debris only specifies taking a stress. You don't skip your action step but obviously this stops your action generally. However, this is relevant for things like the upcoming Rey Falcon title that allows her to boost or rotate arc while stressed, so she could fly through debris and still do those actions.