As a kid I assumed no one knew how old these two were because they were mysterious ninjas, but it turns out Tecmo just redacted their ages in the English translation for obvious reasons. It's funny they went with this route instead of just bumping both characters up to 18 years old. I guess Tomonobu Itagaki refused to tamper with the sanctity of his precious DOA canon 
spoiler
I'm sad to report the PS2 version of DOA2 seems to be one of those early PS2 games that's interlaced to hell and back and will look like a jagged mess no matter how much you upscale it in PCSX2 
Yeah I didnt process original Ashley as a child either, and in that case I was right because she was always canonically 20 lmao. I do prefer the remake changes though.
I do agree that theres a trend worth noting I guess, that the coomer stuff was originally characters that looked like Kasumi and now is characters that looke like Marie Rose. I just... wouldnt have noticed it that way because my brain doesnt process her that way. Namco is probably intentionally baiting for that though. I just didnt think of it. So it confuses me. Subjective experiances I guess.
Yeah. Guess I'm losing the macro implications in the jungle of my micro experience with it.