Looks interesting.
Just a comment:
Note that if Rawshack’s Regulars were to add a different type of squad, perhaps a heavy weapons squad, it would need its own unit roster and could not be combined into the platoon as it would have different skills and weapons.
Surely (if I'm understanding the following section right) a heavy weapons squad gets combined into the platoon via traits?
A putative fourth, half-sized squad, Sanai's Sharpshooters, has 6 members and all are sniper archetype troopers (off the table in the previous entry). Bundled up into Rawshack's Regulars, that would bump the unit's endurance to 42 and give them
Marksman 2D (one sniper per 7 troopers)
Morale - Agreed that morale will be increased for other reasons - experience or desperation (facing enemies noted for not taking prisoners, militia defending home and - especially - family, etc).
Endurance - whilst I agree that casualties do disrupt a unit on a vastly more than linear scale (which is why snipers are so damn effective at pinning a unit down, even if they can't wipe it out), until we see how large-scale combat works in the next preview, there's no garuantee that damage inflicted does impede a unit on a linear one-for-one basis. Taking injury to a person using traveller mechanics, all but wiping out a PCs END score - dropping it from an average 7 to a flatline 0 - only applies a DM-2 to END-related checks.
Standard organisation is fine when explaining basic structure - this only works for 'generic rifle units', obviously; I don't know if armoured merc units are in scope but a quick statement as to what is considered an equivalent unit (so a tank is a 'squad', a squadron a 'platoon' and above more or less matches) might be worth it.
One other comment worth mentioning is the headquarters unit - a squad generally has a squad leader who exists within its numbers, but a platoon commander is usually external to any of the squads he commands, and sometimes has a short section with him, and unlike regimental support assets, this is a front-line combat unit.
For that matter, company or regiments often have a 'headquarters unit' of platoon or larger size.