Thank you for the recommendations, I am thinking of creating two versions. I did the first version earlier, where I created multiple ring buffers (geodesic) on both islands with 0.1 and 2 nautical mile gaps depending on the distance. Then, I intersected the resulting buffers, which gave me polygons. Filtered them until the center polygons remained. Then I created a line (arc segment) that connects the intersection, where the arc is anchored at the centroid of the polygons.
For version 2, I think I'll be using the Thiessen Polygons. I need to find a suitable projection first.
For the voronoi polygons on sphere, I'll be raising this alternative to my colleagues. I haven't use packages before so I am unsure if I want to use it.
Anyway, thank you for pointing out the importance of projection when using Thiessen Polygons. I kinda defaulted on using GCS_WGS84 on every project were working on, and also for introducing concepts such as Densify and Voronoi on Sphere.