Can bombardment-capable units in formations placed on front-line defense or front-line attack still contributes to the battle? The base combat rules imply yes, but I thought it best to be sure.

For clarity, I'm attempting to design an 'integrated' light infantry regiment that contains its own sub-elements, intended primarily for front-line defense and bulk, to be placed in a divison that itself will have dedicated support and command formations. So far it looks something like this:

Light Infantry Regiment
Transport Size: 9,999 tons
Build Cost: 208.5 BP
1755x Rifleman
50x LMG-5 Platoon
25x 5-76mm Mortar Team
1x Batt HQ Van
1x Supply Truck Detachment

A quick mechanics question I realized I don't know the answer to like I thought I did:

Planetary terrain modifies the maximum fortification of ground units, according to Steve's dev posts. Suppose I have 12,000 tons of INF or STA ground units which have reached their maximum fortification level (let's assume the CON units did this and then went somewhere else). On a "normal" terrain with no multipliers this would mean 6x fortification, and a 2,000-ton signature to ship active sensors.

Now suppose the terrain gives a 2x fortification modifier, so the maximum fortification of the same units is now 12x. Does the terrain fortification modifier affect the active signature of the ground units, i.e., will I observe a 2,000-ton signature or a 1,000-ton signature?

I used to assume the former but re-reading the mechanics posts make me think it could be the latter, which is important to know before it becomes important...

Bomb pumped lasers do in fact use lasing rods which produce the laser pulse before they are destroyed.

Fair enough, I was mostly trying to point out that in a bomb-pumped laser, everything happens very fast and once and you're pretty much limited to x-rays as the lifespan of each rod isn't conducive to your standard amplification and controlled release that normal lasers use. The energy in a bomb-pumped laser only makes a single pass through the rod as its primarily x-rays which cannot be reflected.

There are also reactor driven lasers

Yes, but a nuclear reactor is a lot bulkier than a bomb. Not only do you have to have the reactor and laser system, you also need coolant and radiators to keep your reactor from overheating en-route to the target. These kinds of laser would be better suited to being ship (or drone) based than on an expendable platform like a missile.

...Casaba Howitzer

While cool, Casaba's are basically direct hit weapons. They rely on plasma and plasma likes to expand stupid fast and is easily deflected by magnetic fields. They're great for propulsion, but with a range in kilometers you can measure by counting on your fingers and toes, they're not every effective standoff weapons (although good for point defense)

Also worth mentioning that if we are being realistic the focus and wavelength techs are the wrong way round, the more energetic photons would do more damge while a larger focal array should let you keep the beam focused at a greater distance

Higher wavelength photons do diverge less given the same starting diameter. But it's also harder to focus higher wavelength photons so it's easier to have better focusing tech for a weaker laser which could give it a higher range in spite of its higher divergence.

I'm not sure you can make non x-ray bomb pumped laser. From my understanding, the nuclear explosion is what makes the x-rays and there are focusing rods that do their best to focus those x-rays into coherent beams before dying themselves.

It's not like a normal laser with a lasing medium and all that stuff

Two 80k-ton "Ruin" class battleships steamrolled 1.4M tons of enemy fleet in the area around their homeworld. The enemy was one generation behind behind in engine tech but otherwise reasonably at parity. One of the two battleships took significant armor damage and some minor internal damage toward the end of the fight because I was too impatient to retreat and allow shields to recharge from the sanding of Size 1 AMMs.

Some takeaways: The enemy fleet did not use shields, which made our particle lances devastating. Our shields easily tanked significant volleys of ASMs, which the railguns and our own AMMs helped pare down. Ran out of AMMs pretty quickly despite having a 5kt magazine full of Size 1 AMMs, so in the future I might reduce the qty of AMMs and increase the qty of railguns, and/or add some small turreted lasers to add FAC/fighter defense and defend against laser-warhead ASMs. Having my civilian tugs bring these ships to the system enables the use of high-power low-efficiency engines, making these battleships easily outpace any tech-parity foes, which in turn enables us to control the range for beam engagement and, using particle lances/beams, out-hit them in DPS at range or stay entirely outside their effective range.

The next phase is ground assault of the homeworld, which is going to suck. I can "see" a quarter million tons of troops, and it's a forested rift valley, which means a TON more troops are in there. I'm going to need many millions of tons of troops to take this world, specialized infantry and lots and lots of logistics.

DN Pegasus  (Ruin class Dreadnought)      79,935 tons       2,856 Crew       20,069 BP       TCS 1,599    TH 15,000    EM 32,130
9382 km/s      Armour 10-165       Shields 1071-476       HTK 479      Sensors 22/16/0/0      DCR 90-11      PPV 310
Maint Life 1.38 Years     MSP 13,776    AFR 1278%    IFR 17.7%    1YR 7,864    5YR 117,964    Max Repair 1,875 MSP
Troop Capacity 1,000 tons     Magazine 1,740 / 0   
Rear Admiral (Lower Half)    Control Rating 5   BRG   AUX   ENG   CIC   FLG   
Intended Deployment Time: 12 months    Morale Check Required   

Ion Drive  EP3750.00 (4)    Power 15000.0    Fuel Use 246.48%    Signature 3750.00    Explosion 30%
Fuel Capacity 7,000,000 Litres    Range 6.4 billion km (7 days at full power)
Epsilon S119 / R476 Shields (9)     Recharge Time 476 seconds (2.3 per second)

Particle Lance-12-40s (10)    Range 240,000km     TS: 9,382 km/s     Power 37-5    ROF 40       
Particle Beam-6-15s (20)    Range 240,000km     TS: 9,382 km/s     Power 15-5    ROF 15       
10cm Railgun V20/C3 (10x4)    Range 20,000km     TS: 9,382 km/s     Power 3-3     RM 20,000 km    ROF 5       
BFC R256-TS8800 (2)     Max Range: 256,000 km   TS: 8,800 km/s    ECCM-2     96 92 88 84 80 77 73 69 65 61
BFC R256-TS7600 (SW) (3)     Max Range: 256,000 km   TS: 7,600 km/s    ECCM-2     96 92 88 84 80 77 73 69 65 61
Magnetic Mirror Fusion Reactor R76-PB10 (2)     Total Power Output 151.7    Exp 7%
Magnetic Mirror Fusion Reactor R42 (1)     Total Power Output 42.3    Exp 5%

S1 Missile Launcher (40)     Missile Size: 1    Rate of Fire 10
MFC FC6-R5 (20)     Range 6.9m km    Resolution 5   ECCM-1

MD1284k-250t (1)     GPS 80     Range 14.3m km    MCR 1.3m km    Resolution 1
EM2-16 (1)     Sensitivity 16     Detect Sig Strength 1000:  31.6m km
Thermal Sensor TH2-22 (1)     Sensitivity 22     Detect Sig Strength 1000:  37.1m km

Electronic Warfare Jammers:   Fire Control 2    Missile 3