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 
Hi, card-carrying wisher for SoulCalibur 7, and in Project Soul's defense, more than one of Amy's arcade ladder endings involve her killing the weirdo canonically fixated on her. (I'm still upset that they made my childhood main into such a weirdo too; I had to learn other characters after 3 out of sheer disgust with Raph)