I suspect that they wanted a surprise in the show akin to this scenario:
Out comes Kamin's adult son and he looks like Patrick Stewart! Wow! How did they find an actor that looks like a son to Picard?!!
(roll end credits) Oh.....there it is....Daniel Stewart....no wonder, they must be related.
Opening credits are for the main cast, not cameos or guest stars. They did have cards for the guest stars in the opening minute or two of the first act, but again, those are more important parts. A cameo like Daniel Stewart would have been run in the end credits.-Cpthunt (talk) 16:57, June 5, 2016 (UTC)