I want to say overall there are some great interesting and unique units that add a lot to the vanguard gameplay but there are also some that just copy abilities from other vanguard units or other races units. Also some units could use some balance tweeking!

Vanguard Colony Police:
Cool concept but super over powered at the moment, they deal 10 Arc damage with the arc extension module on repeat!
Suggestion:
reduce the damage 7, which is in line with the liquid crystal arc attack or increase the damage slightly and make it a single use attack.

Vanguard Officer:
There are a few units with a lot of their abilities tied to ranks which is interesting but also out of line with the standard units. That's not the main issue though. The main issue that it copies the PUG healing ability and is kind of copy of the Drone Carrier espically once it gets veteran. It just seems all over the place.
Suggestion:
Remove the healing charge, Assault Drones on Vet and Mind's Eye on Expert.
Add something similar to the Psi-fish Mind barrier mod (+6 Psi status resistance and +3 Psi damage resist) OR the Iron Discipline Hero skill (+3 Psi damage resist and immune to psi status and hazard effects) making it a hard unit to control being an officer style unit.
Add some abilities like Rallying Cry (Let's all Allies ignore Moral penalties for 2) or Battle Plan (+10% accuracy and damage to all units for 2)
And/Or Coordinated Strike (makes an enemy 40% easier to hit for 1)
Add something that dispel's negative effects and grants a moral bonus.
Imo this would theme the unit well as a semi Hero unit at lets you use these early game hero skills that fall off later in the game.
Maybe remove the repair drones I'm not as against it having 1 drone ability but having two just makes the drone carrier seem even ♥♥♥♥♥♥ then it already feels.

Vanguard Machine Gunner:
It's missing something! It needs something it is a very mediocre unit with just a Gtling Gun attack.
Some things you could add:
More range 1-2.
4 or 8 power Inflict Cripple (Cripple reduces movement and accuracy by 30%)
Supressive fire attack: 1 aoe attack with low damage (5 maybe) that inflicts stagger OR 8 power to inflict cripple on a 2-3 cd
They definately need something.

Vanguard Sniper:
In the same boat as the machine gunner, it's missing something, it only has the Sniper attack.
Some things you could add:
Starts with a jetpack
1 AP Snapershot/pistol ability for when the unit is staggered
Not entirely sure what they need but just having the sniper attack is very weak compared to other sniper units.

Vanguard Cyborg Trooper:
I really like this one, Laser damage channel is nice and different from the standard soldier, cyborg so you can use the cyborg mods, maybe rethink stagger resist if that is going to be the definining trait of the Heavy Infantry.

Vanguard Heavy Solider & Soldier:
These guys and the Cyborg Trooper are too similar, they all just have a gun and a grenade of some variety. I think you should leave the cyborg trooper mostly alone except for maybe rethinking the stagger resist.
The Heavy soldier is cool to have stagger resist and either kinetic or laser damage.
To make it different you could give it essentially the Tyrant Gauntlet, This is a hero weapon that grants a 14 damage repeating melee attack, +20% bonus charge damage if 3 hexes moved and a 5 range Laser arm cannon that costs 1 AP. And give them a better defence mode like hyper armor? This is obviously a different take on heavy infantry but right now it's just too alike the Soldier which is essentially a tier 2 Trooper which is fine but you don't need 2 of them.

Vanguard Special Forces:
Seems weird, Arc damage channel isn't learned by the Vanguard so it's almost better in the hands Assembly or Syndicate.
I don't like Smart Bullets and Assault dash being on novice, it doesn't feel like the unit is any good until you get novice so I'd give it those abilities from the get go. The other ranked abilities seem less nessciary.
It does need something though, like instead of a standard Arc grenade give it a Stumper Grenade (An arc grenade that can Stun)
Having the Evasive defence mode as standard maybe.
They seem under powered as is but an interesting concept as there aren't any tier 3 infantry units in the standard game.

Vanguard Covert Operative:
Don't like the transfering pain ability, just steals a unqiue mechanic of the Kirko.

Vanguard Scientist Team:
Same issue about the scan, it is kind of thematic with the scientist but it takes away from the Amazon.

The FAV seems cool, a little similar to the attack bike but it's laser attacks are different, maybe give it shields instead of armour so you might want to use it against different damage channels? idk it's not too bad.

APC, Really cool, seems like it might be abuseable as a tier 2, maybe make it a little tougher and make it a tier 3?

Thanks for reading my suggestions but also remember it's your mod and do what you want I know you're putting tons of effort in and these are to try and make it better, thanks for all the work you're putting in and it looks great!