Like the guys have mentioned, drop the armor a few points and get shields.
My own tastes would be to remove the Gauss cannons altogether and put in a 6th CIWS and more lasers. 6 CIWS should make handy work of any missiles and the lasers can be used as backup PD in a pinch.
Can you design a 12cm laser at this stage?
Might be a good idea to play around with the capacitors so you can get either a 1:1 ratio on 'power-needed-to-fire':'power-charged-per-5secs' (or a 2:1 ratio). Just so you are not wasting power like what is happening with the current 12:8 ratio.
If you can get a 12cm laser than you'll need a new beam fire control too ... hmm ... I guess I am suggesting a complete redesign!
You mention the 30secs lag time for incoming ships, I haven't actually paid attention to it before but I thought that the lag time was for sensors only - not movement? So, a ship doing 3000km/s could get out of your Gauss range fairly quick.
It is always good to have backup power generators, but I think you might be better with the extra generators being of the same size which are tied into a multiple of the 'power-charged-per-5secs'. What happens if the larger of the two generators is the one destroyed? I imagine that it has the higher chance of being hit as it takes more space. The explosion will be 3 times as big and more likely to knock other systems out.
As for missiles, I would leave them on some dedicated missile boat that is sitting at range from the JP. You can always mine the area around the JP, that should slow down the attackers