A question that has come up before in some form or another, but still quite important to get a grip on.
WW2 squads varied from the very large twenty-ish man Polish and similar early war Italian squad down to 6-8 mid war British squad. The Polish squad was big and would nearly have to be dealt with by 2 ASL squads or what I would prefer, a squad and a HS. It's not just the rifle count but the number of bodies for stacking, usage number and transport PP purposes.
The Italian early war squad is different in that the platoon had 2 squads, a rifle and LMG squad, the rifle squad had 2 rifle sections with no LMG and the MG squad had 2 LMG sections each with 2 LMG (for a total of 4 LMG/platoon). So the equivalent of an ASL squad would be an Italian section. They later moved to the more usual 3 squads each with 1 LMG per platoon. The mid-late war squad is fine and while the early war squad might seem not, the ASL version might be considered as a smeared average of the 2 rifle and 2 LMG sections (IE 4 squads with 1 LMG each), anyway it appears that at least some early war units quickly moved to 4 uniform sections each with 1 LMG well before the Italians officially moved to the more common organisation.
The British varied from 10-12 early on, as low as 6-7 (light truck capacity?) during the Desert, back up a bit to 8-10 in the ETO. They also had a "Left Behind" system that kept a couple of men behind so if the actual combatants were KIA the squad had a core to rebuild on.
The Germans and Soviets both started with 4 squad platoons each with 12-14 men and ended up with 3 squad platoons each with from 8-11 men. The Soviets did try hardest to keep the squad up to at least 10 men but were officially prepared to reduce a company to as low as 2 platoons each of 2 squads.
The US army squads tried and managed for the most part to keep their squads in the 11-13 range whilst the USMC actually increased their squad size from 8/9 (BAR/rifle) to 14 (or 15 if you include their Navy Corps man/medic).
Most other combatants, at least while they lasted in the war, maintained 10-14 man squads, maybe dropping a man or two.
LMGs: All inherent
LMG are treated the same, regardless of nationality with the exception of German squads who always get spraying fire due to their belt fed MG 34/42. While on the surface that seems wrong, a BAR should not equal a MG 42, a little contemplation might explain. Take a German squad of 10 men, have each man carry 2 tins of MG ammo, each 250 rounds for a total of 5000 rounds, that's roughly 5 minutes of firing maximum. Now while a dedicated HMG squad with it's more lavish allocation of ammo might not baulk at firing at that rate, the normal squad knows that ammo load will have to last them the whole day at least. It's ammo restrictions that tone down the differences between nations. So while the ASL approach is not perfect, it's not unreasonable.
As an aside, the German shift from 1 inherent LMG/squad to 2 really should be reflected by a new squad type. The Heer
468->548 and SS 468->548->658 is a reflection of that. An approach alternative would be to add 1 LMG per X squads (above the Chapter H allocation) where X is the LMG FP, to add an average of 1 FP per squad.
While many armies might de-facto split their squad into a fire base (LMG) and a manoeuvre (rifles/smg), ASL does not distinguish between the base and manoeuvre when deploying, it's a practical game simplification. Otherwise you would have to track which HS has the LMG or double the HS types per nation.
So to the original question. For me the breakpoint is whether there are enough men to provide 2 elements that can act semi-independently. If a DTO British squad with a total of 7 men, squad leader, 4 man manoeuvre rifle section and a 2 man Bren section can function, then I will live with that, though I would prefer to see 4 men per section/HS. It's a question of functionality rather than simple numbers.
Note that all above figures are rough and from memory, it's too early in the morning to trawl through stuff