Nice ships. Sure they can be Hydans with the right colors. I do think that they are beyond TNG era. Kinda pushing towards the 29th century perhaps by then the Fed/Hydran alliance might even collapse and they could be adversaries. They sure have the distinctive Azel look to them.
One thing I have noted is that I have seen that lower pylon appear in some of your Gorn designs as well as 29th century Feds. Though I believe that might be likely, as design does not happen iinside a bubble. For example, notice how when a car mfg makes a hatchback, in a couple years there are 4 manufacturers all making a hatchback that has a similar body style. Same with SUV's. So after a few cenuturies(or less), I could see races starting to borrow from one another so to speak.
Another point and it may not be commom. But I think TMP Hydran designs and Dominion TNG designs are similar.
Dominion ships could almost be TNG era Hydrans with the right texture scheme. They both share a long streamline hull in classes above FF I mean. Though the Dominions hull tends to be wider. Then the Nacels have a similar shape and placement.