The original cast were based on the OVA series. But there are some
differences:
Ryouko was created partially via Washu's ovum, and then through
extensive genetic manipulation (at the very least). I don't know if
you'd consider this to be a clone or not.
Sasami definitely has a crush (at least) on Tenchi in the manga.
There are a lot of implied stuff spread throughout that seems to
indicate more (especially when she talks with Asahi).
Nobuyuki is much more mellow in the manga version. He's a reasonably
nice guy when he appears in vol. 6 and 7. The manga hints at his
ecchi side, but doesn't delve into it.
Washu tends to [be] extremely mischievous (much more so than Sasami)
in the manga. Also, in all the series (to my knowledge), she tends
to like to experiment on Tenchi (in, uh, interesting ways; vol. 7
has one such story). In the manga, I get the impression that she's
less interested in Tenchi as a romantic interest than is implied in
the OVAs. However, she does like to tweak Ryouko and Ayeka a lot.
I think that Mihoshi doesn't get her fair share in this mailing
list. She is quite a bit more than a ditz. She is, after all, a
detective first class. Her reports are apparently extremely thorough
(it took Funaho 5 or so days to read it through). Even Washu notes
that Washu and Mihoshi could probably take on the entire Juraiian
fleet.
She is fleshed out a lot more in the manga. She may be a ditz, but
she does care. A lot. The manga tends to emphasize her klutziness,
but she deeply cares for the people around her, and always has her
heart in the right place. Mihoshi also occasionally exhibits flashes
of brilliant intuition (which probably helps her in her career as a
police detective).
Funaho and Misaki is also in the manga (vol. 6). Misaki is actually
reasonably sane (except around cute objects or people calling her
"obasan"). She displays a "never quit" type of personality, and is
very extraverted. Funaho isn't detailed much further than what's in
the OVA.
Tsunami does appear in the manga (there's a great throw-away banter
between Ryouko and Washuu about the manga being based on the OVA in
vol. 3). She appears once at the behest of Sasami, and another time
to save the gang and one of her trees (children?).
To be technically correct, If I remember correctly, Minagi is the
result of the fusing of both the resultant stuff used to create
Ryouko and Yakage's DNA, and is Ryouko's younger half-sister. From a
fighting standpoint, she's what Ryouko would be if Ryouko were more
disciplined (she was trained by Yakage to be a kind of ultimate
swordsperson). I don't [think] there's no real distinction between
the two physically (though sometimes you can tell them apart because
one of them has their spiked hair going counter-clockwise and the
other clockwise). Minagi turns out to be a really gentle person.
Power-wise, it's not really clear which of the two sisters are more
powerful.
Other significant characters from the manga include: Wan-chan (a
wolf that Sasami befriends), Hiwa (that's her first name; yet
another suitor for Tenchi (kind of like Ukyou [from Ranma])),
Washuu's rival from her Galaxy Academy days (she's the main opponent
in vols. 4-6) and her 3 henchmen, the zen-buddhist monk dude
(Asahi's romantic interest), Asahi's father, and more. However, I
can't remember their names at the moment, so I'll hold off
describing them.
Encyclopedia Tenchicca
