Currently have 5D3, 8-15L, 35L, 50L 100L 70-200L II I have a couple of EX 600’s and the radio trigger.
I saw this post and couldn't resist not to respond, so I registered an account here. LOL
Lenses:
You've got really great set of gears. 50L is a super portrait lens! I really want to get one but I simply have many other gear priorities. I shoot a lot of portraits with my 85L and 135L but I do miss the "standard" look. IMO 50mm gives a very editorial look for fashion and documentary work. I could shoot entirely with one single 85L or 135L, and guess same goes to 50L. 35L is a good environmental portrait lens, so if you like to include a lot of surrounding in your shot, 35L and 50L will be the ones to go, especially indoors! 24L is too wide for portrait.
Camera body
I bought a 5D3 March this year but thought I would need a 2nd camera body for wedding work, so I bought the 1Dx. But foremost, it was my new passion in wildlife photography that pushed me to spend extra bucks on a 1D body. For portraits and weddings, I think 1D is a bit overkill. It's got much better AF tracking in AI Servo mode. The colour come out from LCD screen also look better using AWB.
You situation
As other forum members have pointed out, you have a little gap in your lineup. If I intend to do more events and flash fashion shoots I would go for a 24-70 II. Your wide angle is lacking as well, fisheye maybe too wide? If you do landscape you do need a proper wide angle zoom or perhaps a 24L, 24-70L. And 14L if you wanna go for more extreme perspectives, but then again you've got the fisheye.
If I were you
Our photography area evolves, our style evolves hence our gears evolves. If I were you, I would keep your current lineup. Practice shooting in 35mm and 50mm more, perhaps get a 85L. To be honest, 135L has superb bokeh, but my 70-200LISII's versatility totally wins, the bokeh is not as dreamy, but I can live with it. 135L has been out of my camera bag for a long time now (could also due to the change in my photography interests). I would get a 200/2 or 300/2.8 if I shoot a lot fashion work and need to isolate backgrounds, and given my new passion in wildlife 300/2.8 will probably go into my bag so supplement my new 500L. = )
cheers,
Felix