This question is inspired by the game "Total war: Shogun 2" which is about the Ōnin War. In the game, armies consists of companies of soldiers usually with 100~150 men in each company (IDK if "company" is the right word here). Each company has soldiers that are essentially identical in terms of equipment, social position, and experience. Thus, when you put your army into formation before a battle, one company might have 100 poorly trained and equipped ashigaru spearmen, to their right might be a company of 80 Samurai, all armed with katana. In front of them could be a company of ashigaru armed with firearms imported from the west, and behind might be 100 samurai bowman.
How realistic is this? Would you really see armies with hundred and hundreds of samurai, all formed into units like that? My understand is that samurai were a small minority in Japan, and I would have assumed that a real Japanese army would have only a relatively small number of samurai, who would be in mixed in with commoner militias, and serving as officers.
FYI, the game (my last Total War game) begins at 1545, which means the game covers the late Sengoku, not the Ōnin War.
The question becomes complicated when considering exactly what 1 man in the game is supposed to represent: just 1 man, or many? And what does each unit represent? Based on things written in the Edo, the basic Japanese force designed for independent operation was the sonae ("preparation") made of many gumi or tai ("teams"). The numbers for the sonae varied wildly from a couple of hundred to over a thousand, while a gumi usually numbered in the dozens, or the 30 to 50 size.
A sonae, according to Edo writings, operated in a rough rectangle/oval. Ranged teams form the first group, a bit behind them formed close-quarter infantry, behind whom formed the mounted teams, and immediately behind whom was the commander surrounded in a hollow circle/square by his guards, and then the baggage if they were on the field.
Now, it was pretty unrealistic for all close-quarter men to be armed the exact same way in a team, as each samurai brought whatever they liked. However, the more usual sight was probably a spear and then two swords for the samurai, if the game had a unit like that (it doesn't I don't think), then you can say a team had "essentially the same equipment". Ashigaru would be fairly standard equipped based on their team, except the officer.
So based on composition, a game unit at maximum size is too small to be a sonae. And a sonae would have a wide variety of equipment. On the other hand, the game unit is too large to be a gumi/tai team, for which we would more likely find more-or-less uniform equipment. If we turned down the unit size, assuming 1 man in game represented 1 man in real life, then a game unit could be a team. But the entire 20 card would be taken up by 2 or 3 sonae, where as we would expect to find dozens or more on a single side at a major battlefield. By the way if you found that more than 5 to 8 units became very hard to command without the pause button like I did, well so did the Japanese.
You can read more about composition here
As for how many samurai vs ashigaru there were in an army, we don't really know. All mounted men would be samurai just by a cost and social-status thing, but the definition gets blurry in the middle, and were not strictly defined until the Edo period. I played with some numbers and various assumptions here. If my assumptions are correct, then samurai usually made up between a fifth to a third of the forces.