It's a shame these guys have those mantlings on their helmets. That really makes it hard for us.
It would be easy to assume that we are looking at the same thing in all of these helmets, but I be a lot safer if we didn't.
The guy in the lower right gives us a pretty clear idea of what's going on. There are vertical lines going from near the pivots down to the neck. This might be a sort of armet; and the hinges might be horizontal, or they might be vertical. Then again, it might be a close helmet or a bickoket*, with a one-piece bevor that hinges up from at or near the visor pivots. We really can't tell. The only thing that is certain is that the helmet must open to allow it to be put on and off.
When we turn out attention to the visor, we see what looks like a "full" visor, with the sights formed by a slit. That's not certain, of course. It might be a half visor and a brow reinforce, but I don't think so. The brow seems to jut out more steeply than those on the other helmets in this image.
The one in the lower left may be exactly the same sort of helmet, but with a big wrapper plate over the visor. There does appear to be a strap, and that is consistent with the idea. On the other hand, the brow plate looks like is hugs the forehead more closely than the corresponding plate on the first helmet. At this scale of drawing, it's a very small thing, and it would be easy for an artist to introduce more variation than he had intended. On the other hand, I feel as though this helmet is likely to be one of the closed verities, (armet, bicoque*, etc. ) with a more or less open face.
The helmet in the upper right seems to be the same sort of thing as the one in the lower left. It might also be a helmet with a full visor and a wrapper; sort of like the Earl of Warwick's hat, but with a bit less pointy a visor. A thing I want to call attention to, though, is the way the mantlings of the helmets in this image lay in back. The line of the back is curved in a way that suggests that the underlying helmet has a swept up tail. The mantlings may be trailing in the wind, but that's not at all a sure thing.
I bring up the specter of a sallet-like tail for two reasons...
--The first is the presence of a barbute (or similar helmet) in the group on the left. Such a helmet
could be what's lurking under the mantlings and behind the wrappers. I don't think so, but I don't feel that we can rule it out.
--The second is the swept tails of the helmets in another of the images you posted above.
--The third is the presence of helmets with swept tails in many of the images I have been trying to understand for my illustration project. (I'll try to gather a few of them together and post them later)
The helmet in the upper left shows a very aggressively "v" shaped sight. The other helmets in this image may or may not give us that sort of shape from the front. It depends in part of how much the brow plate (or brow portion of a full visor) protrudes forward. It's also easy to read too much into that "V". It's such a good shape visually that artist might exaggerate it a bit. So... this might be the same sort of helmet as the other, and it might be something more like a "frog mouthed" helm of some construction or another. We see those quite frequently in battle scenes, whether or not we are supposed to take them literally (that's a different argument

)
Mac
*I'm going to see if I can spell this differently each time
