I can't comment on the vaccination aspect of your post.

However we travelled a few times with our little man and it was pretty easy. At that age they don't move or require much amusement so they are pretty easy - feed, sleep and hang out. We went to Darwin at 7 weeks and Canberra twice at 3 and 5 months. If you start solids before then (?) then you can take packet stuff for the week like Rafferties. We had no probs getting into Fiji recently.

The resort areas tend to be fine for these types of diseases so I wouldn't stress yourself.

It will be lovely - go!

PS. I got a baby breeze sling for our recent trip to Fiji and it was the best. Very light and could be used in the pool. I'd recommend it for your holiday.