1 - Canon Everything. (except the amount of torpedo launchers on the Akira, is fine as is.)
+ Excelsior Class Cruiser
+ Miranda Class Light Cruiser (As a Frigate)
+ Ambassador Class
+ Centaur Class (Maybe, it's cute)
- No Excalibur! =D (Thank god flops does not have it, I hate that ship.)
+ Tactical Modules to add small bonuses to the Nebula Class
2 - Cardassians. (They are very cute)
+ Keldon Class Warship
+ Galor Class Warship (perhaps even type I,II and III!? Seeing as only Type III has been mentioned).
+ Hideki Class Frigate
Possible non-canon substitutes are either of the ships from Dominion Wars (a rather obscure game)
+Norin Class Light Cruiser
+ Hutet Class Dreadnought
(Not the Tonga class

)
3 - Pirates / Orions / Something ( I think they could be cool.)
+ Pirate Light Cruiser and Frigate designs from SFC III?
+ Non-Canon designs
+ Sona?
4 - Race Shields =D Brilliant.
+ (imo all race shields should be similar except the Borg)
5 - Keep it conventional
+ None of that 'End Game' Tech...ruins the balance of power imo
+ No Scimitar...maybe as a map object or crazy neutral ship
Lol, my fantasy.