Tawali is a nice resort. Food is good, accommodation is nice, boats are good, house reef is good. The rest of the CLOSE diving is muck diving, with good critters. Good reef diving, however, is at least 45 minutes-to 2 hours away by boat.
Loloata is a small island and has limited "local" interactions. I haven't dived there, myself, so information is limited.
Walindi has good food, nice rooms, and wonderful diving on their day boats. I have only done the liveaboard FeBrina in Kimbe bay, so don't know the travel times to the local sites. The local interactions are very good, since you can go into Kimbe and prowl the market areas. You can also take a side trip to a volcanically heated river for a hot dip.
If you want to dive that area more fully, you can book a trip on the FeBrina (check their schedule). Heck, check out doing back to back trips on the FeBrina. The Rabaul area is very nice, but it would be great to get out to the Witu Islands as well. That time of year is the best to get there.
I have been on both boats and the Stardancer may be the fancier boat, but I tend to prefer the FeBrina. It is captained by Alan Raabe, who has forgotten more about diving in PNG than most captains will ever know. A character, for sure, but he is very into reef conservation and has placed most of the permanent moorings that all the boats are using
Feel free to ask any questions. I will be leaving for PNG Feb 5th to spend a month on the FeBrina doing exploratory diving on the south shore of New Britain Island. I'll let you know what I find.