1. Depends on playstyle. The LMG does pretty insane long range damage (8 dps?) but can only be fired stationary. While the Bar does some alright long range damage (3 dps?) but can be fired on the move, is very dangerous close range, and you can have two of them compared to one lmg. Both upgrades do more damage then Garandes.
2. Bulletins like that are sadly very negligible in the grand scheme of things. If I recall, Accuracy > Reload > cooldown as far as importance. Some Bulletins are outright better then others. (USF veterancy and grenade range come to mind). It should effect both though.
3. The answer is no because I think they are Captain_Riflemen. The captain can get a bulletin to increase his squads veterency so I think they are in fact different bulletin wise. As far as effiency without the bar they are 4 Garande and 1 Thompson. The Thompson is very dangerous up close or mid range, so therefore a Captain or LT is a better version of a rifle squad (combat wise).
4. Rangers cost a lot of MP to call out and maintain. I believe 380 MP? Then I think it's like a 35 MP reinforce cost? If it's super late in the game it can be worth it. The problem with rangers is that they take a long time to start paying themselves off. After gaining some veterancy they begin to outshine most squads. There is no reason to not get their Thompsons. My personal opinion is you want 1 squad of them if you do use them, but if you want more go for it.
1. What is the close range damage of the M1919A6 and the M1918A2 BAR, or is the M1919A6's close damage the same as the long range damage?
2. What would be better for a M1919A6/M1918A2 BAR armed Riflemen squad to have "Live and Learn" (Riflemen gain veterancy 10% faster) or "Recruit Training: Infantry" (Riflemen have 3% increased accuracy)?
4. Are there any bulletins that are available for Ranger squads at the moment that just aren't displayed in the store?
Can M36 Jacksons reliably penetrate Königstigers, Jagdtigers and Elephants with the "General Jackson" (M36 Jacksons have 4% increased armor penetration) bulletin, without HVAP? Does "General Jackson" also affect HVAP? Does "General Jackson" have much of an impact on the armor penetrating capabilities of the M36 Jackson? What are the best M36 Jackson bulletins: "General Jackson," "Clear Skies" (M36 Tank Destroyers gain 5% increased sight range and 4% increased speed), "Shell Rush" (M36 Tank Destroyers have 5% faster weapon reload)?