I seem to remember reading about a January launch (i.e. CES as you say) with shipping laptops expected towards the end of Q1 2020.
Vega vs Navi: IS there any solid information on which of the two it will use?
I don't think there's any solid information; watchers seemed to interpret recently added device IDs in Windows and Linux drivers as belonging to Vega-based APUs with new video engines backported from Navi. Whether that's Renoir or another APU line remains to be seen. There's also rumours that the next batch of APUs might just be a Zen+ die shrink to 7nm rather than a full upgrade to Zen 2.
Given that mobile CPUs and SFF business desktop systems with integrated graphics are where the volume markets are these days, it seems a little odd that AMD lags their APUs behind the standalone desktop and server CPUs so much. The next desktop APUs are only expected mid 2020. I can only assume they are still battling idle power draw issues (especially if Zen 2's PCIe 4.0 is hard to swap out for more the power efficient PCIe 3.0) or that the integration of CPU and GPU via Infinity Fabric is difficult to pull off in practice.