I don't think any Dragonlance content was ever published under the OGL, FWIW. The covered content is limited to the rules and the core(-ish) monster stat blocks. The fiction was never part of the deal (nor should it have been, IMHO).
Interesting. Does that mean If I loosely follow the rules (say mages use mana points which change by shape of moons) and don't use the stats (after all it's just a Ultima spinoff), I probably don't need to worry anything about licensing fee? I really don't think it's going to make any meaningful money anyway.
The Ultima series itself didn't bother to license D&D, so you're fine. Basic ideas of mechanics can't be copyrighted, and no one ever got a patent on "hit points" et. al.
