Re: RG350MYE neck/bridge fit question
What it sounds like the OP is shooting for is keeping the awesome yellow body the 350MYE but get a higher-end neck and bridge. I can certainly understand the appeal of doing that. Also, what makes you assume he'd sell it? Not everyone sells guitars like that. :P If he's going to all the trouble, he's probably more interested in getting it just right for him.
Neck: You'd want one that fits the AANJ on the RG350...which I THINK it has. The problem is, there are a lot of places to look for a replacement neck, but very few are going to be an Ibanez neck with an Ibanez headstock, Ibanez logo, etc, etc, etc.
Maybe contact Ibanez to see if they can hook you up?
To be honest, what I would do is ask "what about this neck bothers me?" and then I'd try to fix that. Once you identify that, I'd take it to a professional and see what it will cost vs. getting a replacement neck. I don't think you'll have much luck with a replacement.
Bridge: Search around and you'll find some info on what tremolo unit fits into what route and so forth. I THINK an OFR fits the Edge III.
Well there isn't a neck with the matching headstock from another guitar as far as I know. I did sell the spare neck I had for my DY 550 a while back, I think for about the equivalent of $300 That's probably the nearest colour match even though it's not exact. I'm not even sure that the older 550 necks would fit a new 350 as the overall neck width changed a little while back.
It really does sound like the OP has effectively bought the wrong guitar if he's just got it and is already looking to switch the neck and the bridge.
I call 'em as I see 'em.