Lens change?

So I recently purchased the EOS-R body. The onlt RF lens I bought was the 70-200 2.8. It is fabulous! All my other lenses work great with the selection ring adapter. My current "walk around" lens is my 24-105 F4 (kit lens with my 5D2). I also have the 16-35 2.8 Mk2. I also have the Sigma 85mm 1.4 ART lens. My only only prime.

I only use the 85 1.4 rarely for portraits, but it is a great portrait lens. I'm not a pro portrait photog (but would like to do more).

So, my question is, should I sell my 85 1.4 and buy a Canon RF 28-70 2.8?

Factors:
- Sell the 85 while there is still a good market for it
- The RF 28-70 2.8 would be a great walk around lens for the EOS-R, and likely be a great portrait lens, although not as fast, and likely not as creamy background, but would be "native" to the camera.
- The 85 1.4 will be available as a portrait lens for my 5D2 (backup, etc), where the 28-70 would be a single-body lens

A collection of thoughts to chew on, in the decision...

1. 28-70 f/2.8 vs. 24-105 f/4...which would you choose to use usually?
   
2. 85 f/1.4 useful if you shoot razor thin DOF shofs, which I think are attractive only to the photographer, and not attractive to a person sitting to have a portrait taken.
   
3. 85mm FL is covered by the 24-105 and the 70-200, and it only is 'better' in max aperture by two f/stops...in the days of digital (vs. film limited to ISO 400) the max aperture is less of a benefit even in low light...just up the ISO by 4x (2EV) ! The bigger max aperture really is valuable in very low light...do you anticipate having many very low light shooting conditions?
   
4. 85mm FL a 'portrait' FL is if you like waist-up shots from 8-10' away; if you want head-and-shoulders that is better shot with 100m. Better facial perspective at 9' with 100mm than at 7.5' with 85mm
   

there is no RF 28-70 f2.8.