Framed corrugated iron shutters left natural would be my preference, colour might be a bit 'try hard' and natural will sit in the environment more easily. Could even make barn doors with it if you prefer that look. The actual barn door fittings are the pricey bits I believe. Our cyclone was made of corrugated iron (by pro shelter builders) and it never ever budged (loud though) so a bit of coastal? wind won't worry it. You don't have much wind going by photo's, all trees seem to be growing upright so a regular build will be fine.

Different kitchen companies use different suppliers. Be it door panels to draw runners. Have a chat to a kitchen company or two that you're thinking of using. Some companies have budget standard hinges and runners as well as high end stuff. Decide on the quality standard rather than branding. Blum have high end and bog standard components for every budget. Polytec make door panels but not sure on the 'shaker' style. Laminex Industries also make panels, again not sure if they make a 'shaker' style.

Very unique. Hope you found it!

If you are aiming for the Scandi look, steer away from any timbers that have a red tone. You may wish to consider a charcoal or black wood wash over the Meranti to maintain some relevance to the Scandi look - best to test this on a sample before addressing the door - Good luck! The team at D'Cruz Design Group