My take on the OP idea: I presume this is more about COH3 seeing as there's little to no chance for a Pacific Theatre (and for good reason).
(0) M36 Jackson Defense Package: Adds an HMG upgrade to the M36 Jackson Tank Destroyer, and also allows the Jackson to hunker down with sandbags to slowly heal over time. (The sandbags are replenished when fully repaired) (Cannot move in hunkered, but can still fire it's main gun and the HMG [if you upgraded it]) (Hunkering can be stopped if all sandbags are destroyed.)
Unlikely to be useful, given it's given to a late-tier unit, and to one that relies on speed and standoff range to be effect against anything. Not very sure what the idea is about, by the time you have Jackson you're already likely to have some sort of effective anti-infantry that's going to be much better than upgrading a TD.
(0) Infiltration Tactics: Infantry can now capture points 50% faster, and decapture enemy points 100% faster.
There's already an ability with that name, and there are also bulletins that let certain USF units capture points faster.
(1) Radio Silence: (Same as the Oberkommando Ability)
I'm personally against copying abilities from other factions. Similar abilities sure, but straight up ripoff?
Also, this ability is redundant with the Code Talkers idea you have, seeing as they both do the same thing.
(2) Deploy Code Talker: Specialized Infantry that can deploy Radios to hide your units. [Said radio works just like a beacon when handling paratroopers] Can deploy from any ambient building.
These sound just like Pathfinders. Given that their sole specialization is just deploying radios to hide units, it's better if this idea was just a passive ability/ upgrade for existing infantry. The last thing this game (and CoH3) needs is more units that do less.
(5) Infiltration Paratroopers: Paratroopers, but with the ability to upgrade for Bazookas to increase anti-tank mobility, or sacrifice some mobility in favor of the M18 Recoil-less rifle.
About the only thing remotely airborne or infiltrate about this company, and at 5CP, AND can deal with armour? Paramarines never jumped into combat either, certainly not with full assortment to deal with every conceivable enemy.
If you want airborne units, they shouldn't be able to upgrade to bazookas. Like Commandos they should have some form of passive camouflage/ stealth capability to avoid high-risk battles. Demolitions might be a useful ability as their main use would be behind-enemy-lines subterfuge rather than a super anti-everything elite infantry; even FJs have many drawbacks, least of all lack of AT firepower.