I think the 3rd Zy will be toast the turn after next (assuming that they can't/don't move straight out of Vega after arriving). We'll have probably the 3rd DD, 1st LSF and 1st CRF available to attack them, and they'll be able to do something like 107% capital damage (ignoring both the damage suffered by the 3rd Zy when they attack and the corresponding loss in damage from one of our fleets).
I don't believe the 1st CRF staying in Draco will prevent the retreat of the 3rd Zy (if they survive), the Nordera could cover their retreat, then kamikaze one of our fleets anyway.
Of course, if the 1st CRF moves into Vega they'll take retreat damage from the Nordera, weak as it is, that would probably only bump a few percent off their offensive capabilities.
And lastly, the 3rd SF is the only fleet that can escape the flag fleet (& friends) counter-attack, heroic sacrifices aside you might as well retreat to Odin and live to fight another day. Otherwise we may lose two fleets in Hydra next turn, yours and one of the 1st CSA & 4th CRF.