>>654764
>>654766
You've made me think, and currently my autism regarding section-level explosives stands here:
<combined rifle and hand grenade
This is your light 35-40mm grenade that looks like a small mortar shell. It has a delayed fuse in the head that is activated by pulling out its pin; and the tail has an impact fuse that is activated by the (passing or impacting) projectile. They should come in thermobaric and white phosphorus variants, with a weight around 250-350g. As a rifle grenade they should have an effective range of 300m, more than that is a waste. As a hand grenade they should be like a modern potato smasher. The big idea is to give every soldier at least half-a-dozen or more, and let them win the average firefight by drowning the enemy in explosions and smoke.
<rocket-propelled rifle grenade
It's basically your heavy grenade. But for maximum versitality in its basic form it can switch between HEAT and HESH, like a miniature rifle grenade version of this:
http://www.military-today.com/firearms/matador.htm
Of course that rocket weights 2.6kg, and our rifle grenade shouldn't be more than 700-1000g. As you said it doesn't need a maximum range more than 550m, and that's already stretching it. Now, to make it even more versitale, it should have a detachable fragmentation sleeve, so that you can still use it against buildings and tanks that are very close without accidentally killing your mates. I think the detachable rocket motor is a good idea, but for a different reason. You could make an other variant that has some electronics to turn it into a missile, like this one:
https://en.wikipedia.org/wiki/Pike_(munition)
I don't see why would you want to launch the heavier grenades without a rocket motor, and I also don't see the point of an intermediate class of grenades between this two. And if you don't intend to use these against targets that are more than 300-500m away, then a knee mortar just seems to be dead weight. Expect if your rifle isn't that good for launching rifle grenades, but then the whole premise of these ideas goes to the trash anyway.
Now for the platoon and company:
<automatic grenade launcher
Something like this:
https://modernfirearms.net/en/grenade-launchers/russia-grenade-launchers/balkan-eng/
And we are going for maximum autism here, therefore the section with the AGL needs a handcart. With 100 grenades the total weight is 112kg, plus the weight of the handcart itself. That isn't a lot even for one person, and you'd have at least 6-7 to drag it into battle.
<ATGM launcher
Look here for inspiration:
https://en.wikipedia.org/wiki/Missile_Moyenne_Port%C3%A9e
But to make it more versitale, it needs an other kind of projectile: a dumb HE rocket. If you replaced all the electronics and whatnot with explosive filling and a fragmentation sleeve, then you'd have something very cheap and spectacularly destructive. Maybe too destructive, because its effectiveness should be more similar to a 75mm infantry gun or a 81mm mortar than to something bigger. And of course we are speaking about a dumb rocket, therefore you'd have to add an additional reticle to the optics to aim it. Anyway, the launcher is 11kg, and the ATGM is 15kg, so they could carry 6-7 of them with a single launcher. And that dumb rocket could be lighter: a Hydra 70 is just 6.5kg, less than half of the ATGM.
I guess the basic ToE for a company with 3 platoons of 3 sections should be would be to appoint one of the platoons as the fire support platoon with a single ATGM launcher and a pair of AGLs. One of its sections get a cart full of rockets, the other two get AGLs. Now, as you can see there are no mortars there, because these weapons are supposed to do their jobs too.