Joelan have their own email addy - contact Falesoa or Sione at email@example.com
Satuiatua is through the samoa-hotels.ws website so you can either go through that website and you'll find a booking/enquiry form - firstname.lastname@example.org
Tailua is also through a group email addy so you'll need to make it clear that you are enquiring about Tailua - email@example.com
You might have to be patient in waiting for a reply for Satuiatua and Tailua given that they are through email addies that have a lot of traffic.
With smaller concerns it's always best to go through the samoa-hotels.ws website where you can, you'll get a quicker response.
Re the buses. They're fun for short trips but when you've got luggage and are going a longer distance you're best to go by cab, hire a car or enquire with the accom provider as to whether they have a pick up service.
Hope this helps
Manuia le aso