Also that's kind of a lot of BP for a grand total of *two* offensive missile launchers, even if your plan is to build a ton of them. If it really is "solar system defense" only, I'd cut down the fuel and deployment time and spare parts/engineering - 1-2 months/2-3 billion km range is MORE than enough for getting anywhere inside the Solar System. 3.2b km range is enough to get to Saturn and back even when it's on the other side of the sun - that's the farthest out you'll probably ever have a colony anytime soon. Build a tanker or 2 if you think you'll need to tool around in the Oort cloud for some reason. I'd cut off an engine or 2, 2200km is slow enough that losing 20-30-40% would make no difference at all in combat capability. Put all the saved space into launchers. Think of using a slower/smaller launcher in exchange in exchange for a bigger volley.
I wouldn't spend MUCH space/BP putting thermal/EM sensors - those are mainly good when exploring to find enemy colonies and ships before they bring up their combat sensors. Anything but a token one on a ship of the line (and every ship inherently has a tiny one for free) is wasted BP/tonnage imo. If it was me I'd lose the CIWS too, and put the saved BP into a class of small gauss-armed point defense ships. At this tech level and for system defense, probably fighters/gunships so you can save the BP and research expense of turrets and tracking. 5000km/s tracking on the CIWS makes em pretty useless for missile defense anyway - they'll leak a LOT, expect the absolute minimum speed missile you'll face to be 10k and most likely higher. I think at this tech level you can make a 8-10-12k speed fighter/gunship, and it will be pleasantly cheap compared to even 1 CIWS. A little cloud of those will give you a nice fleet-defense missile capability, shooting for a later class of anti-missile ships to give you a longer range interception envelope.
And yea, as mentioned, those are pretty awful missiles - I'd cut the range a LOT, and save a ton of weight/BP on the fire control too, to make them faster and better to-hit. At this tech level even 100m km is gonna be about the limit of what you can do without gross inefficiency.
Also if it was me, I'd cut the armor 1-2 levels if it would let me add more launchers - to me it would be more imporant to build a lot of these with as many launchers each as possible than to make each individual one more survivable, beyond enough armor to maybe keep single hits from being internals. Actually probably even then - at long range THESE ships aren't gonna be the targets, it'll be whatever has the active sensor.
Which leads up to the big problem if you haven't addressed it in some other way: none of them does have an offensive sensor - you'll need at least one on SOME ship in order to target the enemy for combat. If you have another scout class ship that's fine, but if you don't it's gonna be an unpleasant surprise...
Without firing up the designer I feel like these ships should be in the 3-4k size range at most with an absolute minimum of 6-8 launchers each, ideally with a magazine of at least about 10 reloads. Everything else is secondary to that. Ideally even smaller so you could build that many more, it's all about total volley size.