Are you coming coastal or inland?
Bairnsdale you need to organise fuel so a little complex but worth the call.
LTV is a little off course, however you pretty much go past there there on your way to Wilsons prom. Fuel available from the club during daylight hours.
No easy fuel solution at Yarram which would be your last port of call.
If you're coming via Melbourne, last port of call is Tooradin, or Moorabbin which is 25 miles from there, or Lilydale / Coldstream just to the East of Melbourne.
PS:
where I can refuel close to the coast near Flinders Island?
and
don't go hand in hand. You're up for 90+ Nautical Miles over water plus around 20+ miles around the Wilsons Prom area with zero landing opportunities.