Which L Lenses are Compatible?

I just got the 1DX, and I would like to know if the L lenses are all compatible to shoot in inclement weather? (i.e. water and dustproof?) I have done some reading and it says the II series lenses are better than the first series, and that some lenses need a front filter.(????) I have the 17-40, 100-400 I, 24-105. and the 500. The reading has been as clear as mud. Any experience or opinions would be appreciated. Thanks.

It's hard to answer your question, the super telephoto lenses can handle light rain and snow, but I wouldn't use them in a rainstorm without rain protection. Dust shouldn't be an issue for all but the old 100-400. That lens will suck in dust and moisture, it is not an really sealed. you can use a sealed filter for the zooms

Thanks Arash.