doa doesn't really do hidden characters so well, haha. ayane turned out to be linked to kasumi during the psx era. hitomi turned out to be linked to ein in doa2u and with the rest they generally pretty much included all their previous characters in each of the new installments. 'cept for genra, he's DEAD dead. haha. they established they're guest game in 5 though.
as for 6, i wouldn't mind if any of the original crew were announced for the base: gen fu, raidou, ein, leon, brad, eliot and alpha. throw in the ghost of genra while you're at it. haha.
priority seats to the normal ones though so: gen fu, ein, leon, brad and eliot.
boss character styles should come in later since nyo and p4 are confirmed.
also no tea no shade, momiji and rachel were just guests from ninja gaiden. props to momiji for being committed to her job though. you can find sis repping NG on new zack island in her promo bikini TO THIS DAY! haha. wouldn't be mad if the NG queens came back. wouldn't be mad if they didn't.