An interesting theory, but I feel like that gives F.O.W.L. a bit too much credit. I mean, if they had the ability to create a cosmic storm, I feel like they could wipe out Scrooge or anyone else they wanted to fairly easily. It also seems like the sort of thing Bradford would disapprove of; too "supervillain" for a guy who want order and simplicity. Why create a cosmic storm to interfere with Della's joyride, when you could simply have sabotaged the Spear of Selene so it blew up in midflight?
That would have been a lot more simple to accomplish, and would have presumably avoided the massive expense incurred when Scrooge launched his search to locate the missing Della. After all, if you could confirm that the ship blew up, there would presumably have been no way Della could have survived. As such, Scrooge wouldn't have tried to find her, knowing that there would be nothing to find. I agree that Bradford would like the idea of a divided Duck family, but I doubt he would have gone to so much effort simply to get Della out of the picture.
Plus, he would undoubtedly have wanted to make sure she was in fact dead, not just vanished without a trace. I think that the board dragging Scrooge from the control room really was about not wanting Scrooge spending his entire fortune in continuing to search for Della. Their whole deal was about running McDuck Enterprises while operating their own agenda from the shadows. If Scrooge had spent all his money, they would have been forced to start all over again after a decade or more of work gaining influence in Scrooge's company.
