I've had fisheye lenses in the past, but they are pretty specialized and I ended up selling them because they just didn't see that much use. There are also cheaper ones available... not to mention rentals... if ever needed for some special purpose. I'd let it go, if it's not used much.
17-40 vs 16-35.... I agree with rick_reno... not sure there's much need for f2.8 on an ultrawide, might not be all that big an upgrade, and it's a lot of money to make that swap.
24-70/2.8... very versatile, definitely get it if you can. Either the original or the Mark II. Both are excellent lenses. I suspect the Mark II will prove to be a good upgrade, but it sure is a lot more expensive!
Yeah, hang onto the 35/1.4 and 135/2... there are times faster lenses are important tools to have at hand. I don't know about the 85/1.8... I'd probably be tempted to keep it. I definitely wouldn't upgrade it to the 85L... unless shooting weddings and getting paid for using it, needing the absolute max speed and mostly only shooting portraits with it. The 85/1.8 is faster focusing and a more generally versatile lens. I definitely wouldn't give up my 135/2 to acquire an 85/1.2L.
So, my line-up might end up being:
I might be tempted to look at the 35/2 USM IS, once it's availabe, as a possible alternative to the 35/1.4.
But, hey, we all have different needs and preferences.