First answering the above dialogue:
10,000 round up always appreciated,
The first and best rule of Aurora.

I would say perhaps 24 months deployment is a bit too much and will get a bit more into that later on why, as if this is meant to be operating by itself then I am assuming there will not be any support ship such as tankers.
You have a 62 days range, however 24 months of deployment. Now it really depends on what is the purpose and missions you are expecting to carry, however, unless you are using this as a scout, survey, or monitoring, which entails lots of stationary duties, you may want to reduce this to anything between 6 to 9 months. I use a 1 to 2 ratio, so if this was me, a 62 days will be accounted for 124 deployment and therefore 4.1 months and I would probably go for 5 reducing tonnage that could be used elsewhere, maybe armour or better shields?
I do not think about fuel in this way. I think of fuel in terms of range, i.e., how far do I need to go to reach the area of operations? If I need to fly 10 b km to garrison a distant frontier and then 10 b km back to Sol when the deployment is over, then designing for 20 to 25 b km of total range makes sense. 30 days? 60 days? Who cares, it doesn't matter to the mission at all.
For deployment time, I always think of this as "time on station". I am confused why so many people think of it as time literally flying around. Most of the time, ships and fleets are stationary whether in port or on deployment as colony garrisons, JP monitors/defenses, escorts (spending much time in orbit loading/unloading), or consolidating positions between offensive maneuvers. I think the point is, it makes no sense to look at the ratio of fuel time and deployment time and say this is too much or that is too little without knowing what the mission is.
For me, my standard in the early game is usually 25 b km and 12 months deployment time. This is usually enough range to reach any system within several jumps and enough time to allow for annual rotations or sustained combat operations. For longer distances I expect tanker support.
Note also that deployment time increases the crew quarters requirement only as t^(1/3), so quite slowly. The difference between 6, 9, and 12 months is very small in tonnage in return for considerable flexibility.
Your biggest problem here is redundancy. What if a lucky strike takes down you unique generator? You will be pretty much defenseless. There is no right or wrong here, meaning you can have 2 or 3 or any other combinations.
I don't bother with partial reactors, I have never had a ship lose its reactor and still be in a fighting state.
I usually go for 2 or 4 reactors depending on ship size. I do try to build my beam ships tough enough to take some bad hits and keep fighting, so the redundancy benefits me on occasion here. Not nearly as important as redundancy in engines, for example, but it's a small enough tonnage difference to be worthwhile IMO.
You have no long range weapons so I don't see the need for the Active Sensors range to exceed the ones of the Passive. To be honest, the Res 1 at 11.1m will pretty much ensure that nothing will get under your nose without you being able to shoot at it.
For an "independent" ship, this depends on the mission. A beam ship still needs to be able to find its targets, after all. That said, I do agree that passive sensors probably have a better payoff than active sensors here.
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For the ship itself:
Shields 20-500
This is quite bad. The rule of thumb for shields should be to have at least the same as one layer of armor, and if you cannot do this efficiently then your tech level is too low for shields. Note that at this tech level, it appears that you get 20 shields for 12 HS, or 1.66... HP/HS. This is a very low rate of HP gain compared to armor, which at this tech level I assume is giving at least 6 HP/HS if not more. So at this tech level it is probably best to use armor instead of shields.
Usually the transition point comes around Delta tech level, sometimes Gamma can be made to work.
Commander Control Rating 1 BRG
I suggest to use the Auxiliary Bridge here, it is only 50 tons (0.5% of total) and you get a second commander slot which will boost crew training and give your junior officers some command experience.
FF-NGC-2058-Drive (2) Power 800.0 Fuel Use 68.36% Signature 400.00 Explosion 12%
Fuel Capacity 816,300 Litres Range 21.5 billion km (62 days at full power)
This propulsion design is borderline, in my opinion. You have 80 HS of engines and about 16 HS of fuel, which is acceptable - a 3:1 ratio is "optimal" in terms of tonnage, however I usually prefer a much larger ratio of engines (10:1, 15:1, even 20:1) to reduce fuel consumption. Fuel logistics are usually a bigger limiter of how effective your fleet can be than whether you can mount 17 lasers or 18 per ship. In this case, I would suggest to stick with the 1.0x engine power multiplier unless you have strong reasons to do otherwise, as this is usually a good value to balance fuel use with speed and range requirements.
Spinal Laser-270k (1) Range 128,000km TS: 4,000 km/s Power 9-2 RM 30,000 km ROF 25
RS Railgun (30) Range 20,000km TS: 4,000 km/s Power 0.75-0.50 RM 20,000 km ROF 10
This is questionable to me. With only one main anti-ship weapon this ship is unlikely to hold up well in combat. I would suggest mounting more lasers for a frigate role. If this ship has a role as a fleet escort, however, then it is fine to have the spinal weapon as a backup capability.
Much worse, however, is the choice to use single-shot railguns. If you pay attention in the component design window, you will see that the single-shot version has about 1/3 the size of the four-shot version, so you are giving up about 25% of your potential firepower by this decision. Better to use full-size railguns unless you have a compelling reason to do otherwise (usually, this means beam fighters).
BFC-Railguns (2061) (1) Max Range: 22,400 km TS: 8,000 km/s ECCM-0 55 11 0 0 0 0 0 0 0 0
This is a bad fire control design. The max range is too short. Point defense fire takes place at 10,000 km, so you have an accuracy multiplier due to range of only 55%. By doubling the range you could improve this to 78%, and personally I would use the 2x range multiplier to get out to 64k range (84%). Conversely, you get no benefit from the 8,000 km/s tracking speed, because your ship only moves at 4,000 km/s and railguns cannot be mounted in turrets, so they must use the greater of the ship's speed or the racial tracking speed tech level (which is probably 2000 km/s here) as their weapon tracking speed. So, in summary: cut the tracking speed in half, increase the BFC range, and this would do much better.
MIL-Radar-200t-2061-1HS (1) GPS 64 Range 11.1m km MCR 995k km Resolution 1
MIL-Radar-200t-2061-100HS (1) GPS 6400 Range 51.3m km Resolution 100
MIL-PAS-Radar-200t-2061 (1) Sensitivity 24.00 Detect Sig Strength 1000: 38.7m km
MIL-IR-200t-2061 (1) Sensitivity 24.00 Detect Sig Strength 1000: 38.7m km
These sensors are probably okay in terms of size, but maybe bigger than they really need to be. For this type of design, I would probably use size-1 sensors for each slot here, expecting long-range detection to happen from other means (e.g., planetary DSTSs). However, this depends on the ships' intended mission.
Do note that in Aurora, space is too big to be effectively patrolled by ships, and (due to jump points) independent solo strikes deep behind enemy lines (such as commerce raids) are largely a fantasy unless the enemy is already beaten. So again, the mission of an "independent" ship needs to be defined realistically in terms of what ships in Aurora are capable of doing well. To me, this usually means garrison, monitoring, escort, or reconnaissance duties rather than raiding missions. Early on, colony garrison missions in particular will require a substantial commitment unless you are playing with a particular spoiler race turned off