Someone also recommended mixing sizes but I don’t want it to look funny

No issues doing what you have proposed on the drawing. What is the size of the door, the left sidelite and the depth of the return panel? If this is close to scale I see no reason it "has" to be 1/2". I think 3/8" all the way will work just fine, size dependent.

here is another quote with some dimensions. This glass contractor wants to go to the ceiling but I'm worried about the ceiling since we aren't tiling there

You can go to the ceiling if you want since there will be no transom but its not necessary and those panels are not large enough to need to be attached to the ceiling. I would not take the glass to the ceiling were it me. In my opinion you can definitely use 3/8" all the way around.