I would love to see an alien as Captain of the next series, and I thought we need another woman. As for Trill, its a recognisable species without being too alien in appearance (which could put off potential new viewers).
As for the Cardassian on the bridge, I did consider having her and a Bajoran male at conn/ops but thought that might be a little cliché. But as you said, many of the crew could have a bad reaction to her being onboard, so leads to a lot of tension that could be explored and (hopefully) resolved.
The Cardassian would have to be female though, after all the first Klingon and Ferengi in Starfleet were female, so that needs to be balanced out.
Huh? Didn't DS9 make a big deal about Nog being the first Ferengi in Starfleet? I can't imagine a female Ferengi would have enough freedom prior to Zek's reforms, (and more likely not Prior to Rom's Nagus-ness) to join Starfleet?
Who were these Female first Klingon and Ferengi, and where does this information come from?
I do like your set up for the premise though
One Day I hope to be the Man my Cat thinks I am
Where are we going? And why are we in this Handbasket?