I think ash has a brighter, chime like tone, especially if you have a maple neck.
My Amercian Strat sounds really bright, and has a maple neck. I guess you can say ash has more "bite" than alder.

Alder, I don't think resonates as well, or maybe it's just the nature of the wood so it will sound a bit warmer and rounder in tone; my 2 made in Mexicos are lots warmer than my American. But they also have rosewood necks. They both sound great for a warmer bluesy kind of tone- rock and as far as I'm concerned, Strats are good for any style.

I love all 3 guitars and find them all very versatile; especially if I tweak the tone with the EQ or pedals. But all 3 sound and feel uniquely different

I doubt I could make my American sound exactly like my MiMs or vice versa, so I'm lucky to have both. I'm not sure what an alder body would sound like with a maple neck, or an ash body with a rosewood fretboard. Maybe if you had an ash body with a rosewood fretboard you could get a little bit of the best of both worlds? I really don't know.