Casting Shipp in a minor role will mean nothing to anyone but the most die-hard fans.
Exactly -- so then what would be the harm? The whole point of an Easter egg is that it'll play like a normal part of the story to those who aren't in on the joke. Remember, the movie The Incredible Hulk
not only included the obvious cameo of Lou Ferrigno as a security guard (and the Hulk's voice), but the much more obscure cameo of Paul Soles, who played the Hulk in the '60s cartoon, as a diner owner. Most people didn't even notice.