Depends on the cirucmstances and the war economy plan.
The US went with the 90 division gamble to keep more men at home in industry, but if they needed to go all Total War like the Europeans and put all men on the front they could have raised 213 divisions.
http://www.history.army.mil/books/70-7_15.htm
AIUI, Marshall and FDR were together (Stimson and King may have been in the room as well) when they first realized how devestating the Ardennes Offensive was turning out to be. Marshall remarked that the gamble made over a larger air force with only a 90 division army was a strategic error.
Between an air force that overmatched its enemies to an outrageous degree to an army crippled by shortages of rifle ammunition and individual replacements to an army that was simply too small in unit numbers to answer all the demands being made of it all over the world.... Marshall was stuck with the realization that any new forces raised in December 1944 would not be in the combat lines until October 1945.
In some ways, US policies regarding mobilization running from 1943 to VJ-Day was not unlike Hitler's demob following the Fall of France. The USA was "planning" the end of WWII two years before it actually did.
Import Mexicans as agricultural workers and for low-skilled factory positions.
Plenty of PoWs for that, though Congress' unilateral action of barring anymore coming to the USA was stupidly political.
Tell any Latin American that if they enroll in the US Army they get US citizenship at the end of the war.
That kind of thing.
Pretty sure that that has always been the case.
OTL there was a scandal when it was realized just how many poor Americans (mostly southerns, iirc, but both white and black) didn't meet Army standards because they grew up malnourished. iTTL, you'd probably get lowered standards - but also a move to improve social equality.
I doubt this. More sent to the factories, but you don't want to see 4F personnel in the ranks. Maybe "limited service" types who were barred from serving overseas. But there was already a lot of that.
Nope. In 1941 75% of the US Army Officer Corps was comprised of White Southerners. And the Navy was worse than that, and the Marines worse yet. The 1941 US Marines, of ALL ranks, were 100% White.
Maquilladoras might also start sooner. Build factories for some stuff in Mexico, Chile, Brazil, wherever, and off load some production there.
The end result could be a rather more developed Latin America.
This was done. Mexico's economy exploded in WWII. Too bad they didn't bother to improve the QC along with volume
With all men in uniform 42-45 there will be very few babies born in those years.
There weren't anyway. My parents were both War Babies, a rare breed.