Honeymoon in Fiji

Hi! My fiance and I are planning to honeymoon in Fiji for 11 or 12 days next June (2012) and I would love some advice on where to stay and what to do. We are active and would really like to dive the best dives, see mantas if possible, swim in the caves, hike in the jungle/see waterfalls, kayak, snorkel, and relax on a gorgeous beach with some drinks :). We'd like to stay in nicer places because hey, its our honeymoon and we'd like some privacy and pampering! Our budget would ideally be about $200-250 per day (or lower if possible of course!)...we'd like to find something all-inclusive or mostly inclusive for part of it.

~Would you recommend staying on 2 or 3 different islands?
~ I was thinking we'd like to stay in the Yasawas for beachy relaxation and Tavenui for the waterfalls/hiking etc. Would you recommend anywhere else or do these 2 chains seem to have what we'd be looking for?
~Any resort recommendations? Blue Lagoon, Octupus etc are mentioned frequently and seem nice, but we want something more on the private side...nice, private villa, private dinners etc...would those places be too rustic/communal for that kind of thing? Or would they be good for a honeymoon?

Thanks so much in advance! :)

Congrats Sonoma!
If you haven't already- scroll down to IPT's post on December 9 (..."Honeymoon")