Hi James,
House and road construction is common in the area. For starters, you may assume that basic tools and machines are available to support on-site concrete mixing (i.e. hand-mixing and machine mixing).
You may also want to explore recent developments on other Torres Strait Islands to see what construction efforts are feasible on a remote island like Saibai. Take a look at this article for inspiration: Modular construction delivers housing for Thursday Island.
I hope this helps!
Regards,
Jean