Yes, I've considered the RF 50/1.8. More of a fall/winter pocket lens than a spring/summer pocket lens...

I'm actually reconsidering the RF 14-35/4L IS. I had initially dismissed it because of the heavy (pre-correction) geometric distortion, an issue with the 16/2.8 as well and for both lenses Canon forces distortion correction in-camera and in DPP. But the corrected IQ is really good, and the lens is quite small, especially by comparison once the adapter is put behind the EF 16-35/4L IS. Although I often travel with the 11-24/4, for some trips I know it's unlikely I'll have a need to go quite that wide and the 14-35 is not a big/heavy addition addition.