But no, the point of both FK and FR is that it creates not just a gameworld, where nothing exists outside what is particularly stated in the game rules, but a 'real world,' where everything has to make sense and have some meaning to it, so that they can all fit together. One of my characters has an keen interest in natural philosophy or 'how things work' (and if I had more time to write publications it might turn out to be interesting). The point of trying to figure out how the FK universe works is to establish as many principles as possible. That does not mean we have to dwell on FR. We can say that in FK, Elves are related to magic in that known only to a few, the Overgod Ao himself in fact concepted the Elven race to model the patterns of the Weave, and Corellon later used the idea to create the Elves from the blood he spilt in battle with Gruumsh. That is to say, Elves in FK are related to magic because down to the molecular level they were constructed to be in tune with the Weave. That and anything else could be the case in FK, so long as it makes sense in the general picture.
The reason we like to derive things from FR is that, although FK is an individual entity, the more we differentiate from FR, the harder it will be for us to maintain some standards and rules. FR offers a huge arsenal of resources that FK is free to draw on so long as FK remains in correspondence to FR - if not in storyline then at least in the background principles.