I can answer that since the only guitars I own other than my own brand and one Les Paul are USA made Charvels.
1) Unfortunately the Mexivels are worlds away from the USA and Japanese Pro-Mods. The fret work alone is pretty horrible, done with a lack of care and ending with a neck that feels different than any other Charvel due to it. The USA and Japanese Pro-mods had the frets beveled and dressed on the ends nearly the same way as the custom shop guitars just with a little less time spent on them than a custom to speed up production. They also had the tangs clipped back short and the end of the slots filled with wood filler just like a custom shop Charvel to help prevent fret poke. The Mexivels frets do not have the tangs clipped back and slot filled and they're just hastily way over beveled (not a good thing) and hardly dressed just like any Mexican strat unfortunately. They're about as far from a real Charvel as the 80's pointy head Japanese imports are. FMIC has watered down the brand to make an extra buck and it shows, the move to Japan for the pro-mods was bad enough but at least the quality was still there.
You can see the frets on the Mexican here how crazy far the bevel is with tangs that are way out past the playing surface of the fret...
https://www.ebay.com/itm/Charvel-Pro-Mod ... 2c7ecd0421
and compare them to the USA here that has much more playing surface with frets that cover the whole width of the board...
https://www.ebay.com/itm/Charvel-USA-Pro ... 258b702988
2) Alder is a very neutral wood EQ wise with no big push or scoop in the bass, mid or treble. So to compare swamp ash to that, in general it has a mid scoop with bass and treble similar to alder. Some say swamp as is brighter than alder with a bigger bottom but I think it's actually the mid scoop that's making the highs and lows more pronounced and not an actual brighter wood. Swamp ash is also much more inconsistent in tone than alder. Of all the woods used for guitar bodies, alder is the most consistent from one to the next. Of course it varies from piece to piece but that variance is far less than from piece to piece of swamp ash.
3) I have a DeMartini neck on one of my custom shop Charvels (which is not a DeMartini, it's a quirky factory made frankenstein of sorts using an EVH body route and DeMartini neck) and it's the 3rd thinnest Charvel neck I've come across in owning a bunch, playing even more (Music Zoo is near me) and working on other peoples. The pointy head reissues have the thinnest necks, then the 2004 red/white bullseye reissues then the DeMartini, then the standard custom shop "San Dimas" shape, then the pro-mods just a hair thicker than that. Of course all the customs do vary since they have more time being hand sanded than the Pro-mods do but that's what I've found in general when comparing them.
I didn't know my custom had the DeMartini neck 'til the first time I took it apart to adjust the truss rod and found this cool surprise on the heel...
