Creating an IK rig to bake into Mecanim

I'm trying to create animations for Mecanim in Blender. After doing a bit of research, I know that if you want to put an IK animation in Mecanim (say, for a walk cycle), you need to bake the animation before exporting it to FBX. But I would also like to make the rig I'm using for my animation compatible with Mecanim, so that I can import it as a Humanoid without having to change how the bones are parented. Right now, I have my rig's feet and hands parented to the IK bones, but to import the rig as a Humanoid they need to be parented to the lower legs/arms, respectively. Does anyone know of a way I can have my cake and eat it, too? I've already considered creating multiple armatures, but I'd like to know if there's an easier solution.

A related, but less pressing question I have is can you used Unity's IK on a Generic rig, or does your rig have to be a Humanoid?

Thanks!