As long as the edges are straight and square to the faces, you should have no issues. Gluing them together will require moderate claping pressure, so I hope you have some long clamps OR can work with them in pairs until the final assembly.
Your biggest concern is to get them as level across as possible to reduce the amount of "corrective" sanding OR planing afterward.
Planing the faces has little if anything to do with planing and straightening the edges.
The answer to your question will only be as detailed and specific as the question is detailed and specific. Good questions also include a sketch or a photo that illustrates your issue. (:< D)