Weapons-based principles can translate very well to empty-hand principles. The ease of transition also depends upon which Filipino martial art you practice. For example, (and from my limited perspective) the transition from weapons-based to empty-hands-based technique in Pekiti Tirsia Arnis seems virtually seemless, which makes this an excellent FMA to study if one is interested in learning an efficient empty-hand system "from the ground up." Similarly, the principles of Estacada-Weapons are exactly the same as Estacada striking, locking, throwing, etc. On the other hand, San Miguel Eskrima does not have an empty-hand curriculum (aside from Combat Judo) of which I am aware: learning how to fight without a weapon using this system as a base would involve extrapolating the empty-hand principles from the weapons-based principles.
Sometimes you might hear people say (something like) "It's easy to learn empty-hands in the FMA's because all the movements and principles are learned in the weapons-based practice." I don't think that this kind of statement is entirely true. I would say that if you are interested in using the FMA's as a foundation for empty-hand self-defence, then you will have to spend as much time practicing the empty-hand component as the weapons component. It's fine to say, "O.K., here I would throw a kick, or lock my opponent up, or throw him, etc." (based on such-and-such principles) - it's entirely different to be able to kick, lock, or throw with power and efficiency.
Best,
Steve Lamade