As far as flight suits and helmets are concerned, we've only seen X & Y-Wing pilots wearing the standard APH6B style helmets with orange flight suits, in Jedi where we got introduced to the A & B-Wings we saw pilots with both different colored flight suits and different styles of helmets. So there's really nothing contradictory here not to mention this is, obviously, before the Alliance where the Rebellion is still operating in cells so there really wouldn't be a standard uniform as of yet so these could easily be what they normally wear where they come from.
The third and fourth pictures MJF posted show the ROTJ Y-wing helmet. These guys:
My headcanon since the late '80s had been that the pilots we saw in the first two films were all part of one unit of the Rebellion, made largely of Clone War and post-Clone War Republic Navy vets who defected to the Rebellion due to the Empire getting more and more not what they signed up for. And all the new flight gear we saw in Jedi were for other system/sector flying groups that had joined the Rebellion later on or were operating elsewhere. Reference Leia and Vader mentioning the Rebel fleet massing all in one place -- something we can presume has never happed up to that point. Maybe the gear for the A- and B-wings was purpose-developed for those craft by whoever was making the ships, no problem. Never got the new gear for the Y-wings except by some version of what I mention above -- that that's just some other world's defense forces' gear.
As for contradicting the EU, why not? If they're no longer beholden to the EU then why go out of your way to to try to stick to it? By tossing the EU out this means the writers are free to follow or contradict the EU as they please and create a brand new canon without all of the old (EU) canon getting in the way.
Beause the A-wing backstory was one of the good bits. The Battle of Yavin was the first real toe-to-toe Rebel and Imperial forces had had. It showed Rebel leadership the strengths and weaknesses of their existing fighters. Dodonna saw that the Rebels needed something faster to fly cover for their heavier and slower fighters. The A-wing was the F-16 developed to protect the F-4 and F-15 strikefighter/fighter-bomber workhorses. Worked just fine for decades in the EU, do't see why it needed to be overwritten. *shrug* Far, far less of a problem than crystals focusing lightsaber blades or five-mile Super Star Destroyers or the myth of there being a "Rogue Squadron" or like that.
Once again...IMHO... The old EU sucked. Glad it's gone.
I take a more piecemeal approach. A lot worked great. A lot was awful. I don't see the need to flush the good along with the bad.
[snipping spculations that are somewhat in line with mine] You can also see in Return of the Jedi that in the background there are mixes of suits and helmets. "Hey we need to attack that Star Destroyer, send all 12 of our A-Wings. What's that? Only 8 of the pilots have green flight suits. I guess we only send 8 then. We must have consistency in Rebellion. Oh, speaking of which, someone tell Solo to stop wearing civilian clothes."
I also will state that like the F-35, the helmet is specialized for the aircraft because it ties into the cameras and the HUD is built in. But I see no canon evidence that any known gear in the rebellion must be utilized with a particular craft.
All the way back to when ROTJ first came out, we had A-wings, Y-wings, and X-wings all in Red Squadron, so I'm not fussed over mixing fighter types in a squadron. But whatever the squadron, all the A-wing pilots had the same type of flight gear. All the B-wing pilots had the same type of flight gear. All the Y-wing pilots had the same type of flight gear. Some minor variations of details and color, but negligible. It just appeared that the Rebels had suddenly gone from one catchall flight suit to one for each type of craft they flew -- whatever color and detail variation there might be.
And from Empire on, Han was wearing the Alliance uniform trousers, at least. Same ones Luke was wearing at the end of ANH. Providing his own camouflage and cold-weather gear was a way to save a resource-strapped Rebellion the effort and expense of getting some for him.
I posted that little comment as a result of an earlier post about whether the troopers survived. I figure readers of this thread might like an official LFL answer instead of a fanboy answer/speculation. I know I do.
Ah. Well, I consider the very first Star Wars film to come out to be a pretty definitive answer. *chuckle* My take on just about anything in Star Wars is to presume no one's dead unless there's an inarguable corpse -- and sometimes not even then.
--Jonah