Which is why most chinese divisions are better represented as militia.
Yes and no.
The "professional" Chinese Red Army originally was supplied through defections from the NRA (CHI Army) and stealing supplies during the interwar period. Food, clothing, housing was often provided by the local populace (which unlike the NRA, the CRA did not steal from the population in order to feed the troops). in most combat battles, CRA would have it's rank swell from temporary local militia that were given weapons by the CRA. Hit and run was the primary doctrine of choice (after the disastrous southern strategy failed), with stolen Japanese equipment commonly used by the CRA (I would wager over half of working weapons used by the ERA were stolen from killed Japanese soldiers or given by deserting/fake collaborationist divisions).
In this regard, the standing Infantry Army of the CRA is very small. Most battles by the CRA should contain militia that are rapidly mobilized/disbanded during the second Sino-Japanese War (100 divisions offensive decision is an example from 1936 CCIP).
Post-war however, the CRA changed significantly. One of the reasons Jiang Jieshi did not want Japan to surrender so soon was because he had no troops in position to accept Japanese surrender. A majority of Japanese superior weaponry was surrendered to local communist militia or soviet troops, who gave it to the CRA. This enabled over 450.000 experienced and battle hardened Eighth Route Army militia to "upgrade" to infantry (assuming some of the divisions weren't already infantry due to the accumulation of stolen weapons) and is one of the reasons why CHC did not immediately fold after the war.
IC wasn't a major issue for CHC, nor was manpower, supplies were. If supplies were the cost for Infantry instead of IC, CHC would still not be able to field many units since historically, SOV supported CHI much more than CHC (one could say they barely supported CHC) until after WWII ended.
The army grew from 30,000 troops in July 1937 to 156,000 in 1938 and 400,000 in 1940. Reduced to about 300,000 by the fierce fighting between 1941 and 1944, its size almost doubled to a total of 600,000 men in 1945.
Following the end of World War II, the 18th Army Group was incorporated into the new People's Liberation Army. Units from the former 8th Route Army were active in the 1948 capture of Northeast China from the Nationalists, which placed the communist forces in a position to take North China and turn the civil war in their favour.
Currently in game, it is very hard for CHC with ~3IC of production to produce/maintain 60 divisions without events. If supplies were the requirement, then it'd be much easier (although there is no abstraction of captured supplies in game, but that can be done via event).
As for the other factions,
CHI was focused on INF and later switched to MOT during the civil war.
CGX was an industrial heartland for CHI during the second Sino-Japanese war and provided some of the best hometrained divisions, so they should be INF.
Edit: The Chinese Wiki OOB page for ERA in 1945 has a cited link of 1,028,893 soldiers in the Eighth Route Army, which is different than the uncited quote above from English Wiki, so I guess I need to re-research the OOB once I get to 1936. I don't think it is remotely possible for CHC to get 103 divisions ingame with its starting IC. Here's an image of captured artillery:
Also, a gold mine of
CHC leaders here.