Even Seth MacFarlane has more clout than Bryan Singer.
Seth MacFarlane has more upward mobility in Hollywood than Bryan Singer does and here's why...
1. Seth MacFarlane has his own animation empire now. Bryan Singer has no empire of any sort.
2. Seth MacFarlane can put "The 1978 Battlestar Galactica Series" into an episode of "Family Guy" anytime he wants to. Even if the new "Galactica" footage Seth MacFarlane put into "Family Guy"
was animated (a cartoon), and designed to spoof the 1978 series, it would still be new "1978 Battlestar Galactica" footage, which is infinitely more than what Bryan Singer could ever do.