Would you bother with the 12mm F2, 17mm f1.8 or 45mm f1.8 if you had the 12-40 f2.8 Pro?

EyeMac wrote:

Sad but true, buying a new lens tends to get me motivated to go out and take more photographs!

I have the 12-40 f2.8 pro that stays on my camera pretty much full time.

I don't have the 12-40, but I have the 12-60.  It's not a straight f2.8, but it is the fastest zoom I have.  But I don't use it that much, rather the 14-150 stays on in the day, and at night I'm likely to use the 17/1.8  If I didn't have the 14-150, the 12-60 would get more use, but so would the 17... because the 12-60 is kind of chunky, and sometimes you don't want that much on the front of the camera.  The 12-40 might be 'fast enough' for my night shooting, but for street, I like the 17 because it is less obtrusive.  Don't know how much that concerns you

I have the 9-18 that I use occasionally. I also have the cheap Panasonic 25 f1.7 that I bought for $99, I'm not too fussed about this one so it might go but there are loads on the online markets so not worth much. I have the cheap 40-150 that gets occasional use. My last lens is the 75-300 which is rarely used and seems like a bit of a white elephant for me. I am tempted to sell the 75-300 to get either the 12, 17 or 45 but not convinced I will use it!

My last thought is that I should ditch the 9-18, 25, 40-150 and 75-300 and get the 40-150 f2.8 pro plus the teleconverter that is fore sale reasonably on an online trade site!

Would you put all your eggs in the two 'Pro' zoom basket?

I wouldn't dump the 9-18, I wouldn't want to give up the wide end.  Now if I had a prime in the 7-9 range, I might give up.  The 40-150 I no longer use, having replaced it and the 12-50 w the 14-150.  
If you don't need the reach of the 75-300, don't keep it.  I have the 100-300, and while I don't use it a lot, I wouldn't give it up (unless I managed to acquire the 300 Pro)

I wouldn't want to have the 12-40, 40-150 pro pair alone, as I prefer a lighter kit.  If you put more emphasis on quality than portability, than the pro lenses may be the best solution for you.

As for supplementing w primes, do you need the extra light?  Or shallower DoF?  Or do you sometimes want a smaller lens?  If you can't answer yes to any of those, you don't need any (additional) primes.