I stayed at Ramon's village in Aug '01 and at Steve and Becky's in Aug '02 (which is associated with Ramon's and right across the street so you get to use their pool, etc). It's my favorite place in the world!! And here are some answers to some of your questions:
1) I've never been in January so can't help with that one, sorry!
2) I've never worn bug spray at any time while on the island but everyone else says it's bad so I would at least take some... Maybe it's the time of year but I've never had a problem
3) Of the places I've eaten at so far Sweet Basil is my favorite (North of the cut, follow the only road and it's on your left)
4) Daytrip to Lamanai was educational and interesting, cavetubing was very fun *make sure you take one of those disposable waterproof cameras, you'll understand why when you get there*, and the catamaran sail to Caye Caulker with stops at Hol Chan and Shark Ray for snorkeling was awesome -- very relaxing and we saw a rainbow on the sail back. We booked all of our tours through Ramon's and I can't remember who did Lamanai and cavetubing but the catamanran sail was with Hustler.
5) For souvenirs I like the boutique at the Holiday Hotel, and the jewelry shop in Fido's courtyard owned by Elizabeth... lots of cool places.
6) Ramon's gives you filtered water in your room everyday and usually if you order water in a restaurant it comes bottled.
7) already been answered
8) Nobody could have told me how to prepare, I was absolutely blown away when I went... I fell in love with the place and the people
If you would like to see some pictures from Ramon's you can check them out at: http://albums.photo.epson.com/j/AlbumList?u=4093829
Not all of them are mine, somebody in our tour group sent me his as well....
Hope this incredibly long reply helps!!