The Trade Federation 'Donut' ships aren't warships by default, but are giant transport freighters that were modified for combat later on. Trust me, an the Donut has so many openings that an Imperator would rip it to shreds.
As for the N-1 being more advanced than a TIE Interceptor, please keep in mind that the N-1s were produced in extremely limited numbers to protect Naboo and not intended as a mass-produced fighter. I'm positive that the TIE Interceptors were designed along the philosophy of reasonably cheap and efficient use of technology as opposed to the N-1 which probably incorporated different tech which had similar functions but that were undoubtedly more expensive. Again, considering that the Naboo were only creating a fighter meant to defend their homeworld as well as serve as an ornamental showpiece, they probably didn't mind forking over the credits to create the N-1.
And before anyone points out that the Naboo still shouldn't possess fighters that surpass the best that Imperial tech has to offer, well remember they didn't. Comparing the TIE Interceptor to the N-1 is foolish because they had different philosophies regarding their construction. Comparing the N-1 to say, the TIE Defender, or even the TIE Avenger is a bit more reasonable since all craft were produced in limited quantities and all have similar capabilities (though those two TIEs easily outgun, outmaneuver and outrun the N-1).
Chief, the Z-95 is going to be rebuilt from scratch as well as the Rebel Transport using the existing models as templates or guides. One question I do have regarding the Z-95 is the cockpit. Are there really any sources that should be considered as "canon" since they all generally vary to begin with, or should I just design it based on observations of other Rebel craft (thinking of "antiquating" the X-wing's cockpit design and possibly employ ideas from the A-wing since both have the bubble canopy). The only real clear references that I'm familiar with come straight from the X-wing PC game series.