NO! NO! Don't add to the confusion! Macross7 is NOT based on DYRL's chain of events. DYRL is a movie within the Macross universe where Max and Milia play themselves. No I'm not joking.
Macross7's storyline is a direct sequel to the Macross TV series. Macross7's Max and Milia were married as Miclones while flying a valkyrie around as portrayed in the TV series. Macross7 only borrows things VISUALLY from DYRL, one of them being Exedol's appearance.
Within the story, wouldn't DYRL's Exedol just be styled after the CURRENT appearance of the real-life one, as opposed to how he looked then?
Even in the real world, "historical" movies often change things drastically to appeal to the masses that already "know" how something happened.
Or just to spite historians, I think.
...
Anyways, it would be logical to assume that Exedol in DYRL was styled after his appearance at the time of the movie so as to avoid confusing audience members who had seen recent pictures of him.