I just looked at one of my 3000 point lists and it outnumbers your list by 72 Men and 2 Vehicles...I have a 1500 point list that has similar numbers to this list though.
My point been that building an IG list should be about keeping every unit as cheap as possible, while still giving it everything it needs to be efficient and capable in whatever role it has...usually equates to type and number of weapons and maxing out on warm bodies.
I can see 315 pts on Upgardes I wouldn't take for various reasons, and that's without accounting for some weapons choices (HF's and the mix of weapons within the same unit), and the choice of some units that aren't worth fielding (Techpriests).
That said, at 3000 points and for a Campaign you can take whatever you feel like and bugger the competitiveness of the list...which is fine
Some (most) of your builds are fine, others I would change -
- mixing SW's in the same squad is inefficient...give them all the same type so they are specialised - this goes for the CCS & Vet squads.
- HF's aren't worth 4x's the cost of the standard Flamer, plus giving them to your BS4 Vets isn't taking advantage of that BS at all and just makes them only as good as standard Guardsmen...Plasma/Melta for Vets is by far the best choice.
- on those dual HF Chimeras...I would never swap out the Turret Multi-laser because it is a versatile and capable weapon that has dual roles of anti- AV and Infantry. Also I doubt that anyone will move/stay in front of a static Chimera that's toting 2 templates, plus if you move at all you can only fire off one of them anyway.
The best Chimera builds are ML/HF if constantly mobile, ML/HB if acting as a firebase for some turns...this depends on what unit you're transporting and what weapons they have...Plasma = static, Melta = mobile.
I would give the CCS a Chimera to keep it mobile so it can react quicker to any threat, plus seen as the transport offers some protection you could drop some of that expensive protection you have...80 pts spent to keep 5 guys alive
Nobody takes EA...simply too expensive for the bonuses it provides.
Camo Netting is iffy because for it to work the vehicles already need to be in cover so you're getting a Cover save anyway, plus seen as you have 2 Medusas only one needs to be in cover (5o% of it) and the other one gets that save also.
The Bassie has ECC plus seen as it's usually firing indirectly it should already be in cover.
Doctrines are also too expensive for what they grant, plus you could get a whole other unit for that 120 points...4+ Cover Saves aren't hard to get and it's free, plus the Chimeras are protecting them somewhat anyway.
Obviously feel free to ignore what I've written, as in the end the bit that I underlined and bolded is likely more important anyway...best of luck in the Campaign