Egypt would not be involving itself in this. It has other problems than actually defeating Ethiopia in a grand master plan through proxies.This looks like it could be a proxy war with the likes of Djibouti, Egypt, and Somalia on one side and Somaliland, Ethiopia and maybe others on the otherside (I'm already getting a sense that some western countries are putting pressure on Djibouti to back down but we'll see where it goes).
This ain't gonna be no small thing like Laascaanood but a bigger war that could destabilize both SL and Djibouti.
Or maybe it's nothing and the fat man is bluffing, I see some SL still doing politics in the face of this potential threat so who knows.