Cubase Rewire Reason: Where Mix?

I usually use Cubase for audio tracks and Reason for drum, synth, bass, pads in rewire mode (so I have 5 or 6 tracks in Reason). My midi parts are in Reason sequencer and audio parts are in Cubase. I’ll would mix all tracks with Cubase. In this case I must activate more re-wire channels but only the first couple is linked as a stereo channel (Mix L+R) and the other are mono. For each couple of these I must define the pan and I rout them in a new stereo group channel. I’ve tried to set the same name for one of this separated couple but the result is the same.
My questions are:

1.Is possibile to have 2 mono re-wire channels directly linked as stereo channel (as Mix L+R)?

2.In terms of quality of result, is indifferent to mix in Cubase or in Reason (using only the first couple of re-wire ch)?

Thanks

This is probably a Reason side thing… When I rewire Ableton I get stereo pairs instantly.

Reason is also a few bars out of sync when rewired to Cubase… I can’t believe this is still present…