With mebhaighl indicating strong magic I would expect that the elven navy is very interested in Cerilia, possibly it could be a nursery for their ships to grow in?

An interesting idea is planetary alignments causing temporary surges is (awn) mebhaighl, if they can affect the tides, why not mebhaighl?

An opposing idea is perhaps that mebhaighl interferes with spelljamming helms, in which case you would have relatively rare visits to the surface (keeping it isolated). So for example you could rule that helms can be overloaded if near a province where a realm spell was used, given the cost of helms that would keep the jammers very wary of going down to the surface, while leaving the rest of the sphere open for BR-themed specials.

Given that the Elves use living ships and are more closely tied to mebhaighl you could have them more able to land, or endure mebhaighl storms in space giving them an edge against others and reason to make something special of the sphere.