Pete,
The link you provided seems to give you the information you need to make your decision -- Manta Ray Divers/Hotel is almost fully operational if you want to go with them. They mentioned that in about 60-90 days everything should be back to "normal". Question for you is if you would like to be in Yap during the heart of their reconstruction period. Supplies will be limited and services in disarray, but it will also be a time when the resilience and tenacity of the good people who live there will be most evident.
Saipan had an indirect hit from Supertyphoon Pongsona (180-250 mph winds; Guam and Rota had direct hits) in 2002 and despite the damage I saw, people hunkered down, regrouped and relied on their familes, communities, government, and relief agencies to move on with their lives. It was nice to see the collective efforts of all. If you go to Yap now or in the next few weeks, you'll see some of the rebuilding and, if it so suits you, you can take part in it through many of the volunteer organizations that have extended their help to Yap. In any event, I think that Yap's economy could use your dollars, especially any of the mom & pop stores that happened to survive the storm. Even dollars you spend at Manta Ray Divers will make their way around the local economy because of the communal nature of money in many parts of Micronesia -- wages and tips to hotel/dive staff will be shared with the extended family in this time of great need.
Good luck, and please post a report when you get back.
