Beaches & Whales in Ha'apai vs Vava'u

I am heading to Tonga next month and would like some help please...

Is it worth visiting both Ha'apai and Va'vau? The flights with the Kingdom of Tonga pass is basically the same as just going to Va'vau and back. Basically I am keen to see some gorgeous beaches although don't want the whole holiday to be totally sleepy so would like some action (markets etc) in Vava'u too.

Is it better (or more likely) to see whales in Ha'apai (bearing in mind this will be toward the end of whale season)? A lot of posters seem to think it is cheaper and less people around so therefore better.

Also what are the best beaches/part of the island to stay on in both? I have heard Foa in Ha'api is the only decent beach unless you head to an island? Seeing whales from my guesthouse would be amazing! I have heard this is possible on Uoleva island off Ha'apai.

And finally is it advisable to get alcohol duty free? Also is it advisable to bring snack foods etc as is food pretty pricey like Rarotonga?

Thanks so much in advance.

Edited by: tessanorth

Bear in mind that having fewer people around could mean that boat trips do not run due to lack of customers. It being the end of the whale watching season will also reduce the number of boats willing to make the trip. You might have more luck getting on a boat from Vava'u. I'd recommend doing the whale watching early on in your trip - the later it gets, the less interested the whales are in being watched...