Yeah, all 3rd-party DX/EF-S/Crop lenses should fit on all FF bodies (in theory), because Nikon/Pentax/Sony don't have any special things in the mount that stop you mounting crop lenses on FF bodies (Nikon actively encourage it with their 'DX Crop Mode' on their FF bodies).
Also, seeing as most 3rd-party lenses have to mount on Nikons with their longer-flange distance, the rear element has to be further from the sensor than EFs lenses, so a canon FF mirror shouldn't hit it. They don't redesign their lenses (optically) for different mounts, they just use a thicker mount for canon, thinner for nikon.

I've seen the Samyang 8mm Fisheye mounted on a 5D2, it makes a weird vignetting image because of the hood, you can (carefully) hacksaw the hood off to make it a nice black-edged fisheye (not quite a circle, not quite a FF fisheye) if you don't mind a bit of cropping a lot of people like the effect because Samyang fisheyes are stereographic (compress the borders less).
But you should be able to safely mount any Samyang/Sigma/Tamron/NikonDX/PentaxDA lenses on your FF bodies (should, if you try it and break something don't blame me).