The 980 is a spunky-great design. The wide shuttlebay on your Galaxy with your new saucer has really come into its own
I like how you have the nacelles raised on the Pax--the only helpful hint might be to make the nacelles a bit thinner to keep it sleek. Great saucer on that. I've been waiting for someone to place a super reliant saucer on a super-refit secondary hull. You might play around with that a bit more.
Something about your defender really speaks to me. The nacelle pairs come from Stargazer, but I wonder what it might look like if you omitted the bottom nacelle and its supporting structure--so that you had only the upper section of the stargazer nacelle supports.
That might look cool on its own.