if you can wait, there's a new mirrorless coming out from sony, the a9 series camera. not much known about it but it sure gave me a morning glory. :P
aside that.. the 35mm makes a good walk around, but the 55 1.8 is probably the lens for you if you want cat shots. 24-70 is already plenty wide to me, 16-35 would be over kill but works for landscapes and tight areas.
Thanks - I did hear about the possible A9. Very good point. I have Canon's 16-35f4L and together with 70-300L, they became my favorite pairing for travel (I also carried 35L for nights and low light situations).
I tend to gravitate to wider lenses - between 50 and 35, I do prefer 35. There is supposedly an AF 35mm coming from Zeiss (not the Loxia).
Perhaps waiting is the way to go...