Your eLicenser licence for Absolute can only be on one USB eLicenser at a time. If you want a second USB eLicenser with an Absolute licence, you would have to purchase a second licence.
Steinberg are still working on their plans to transition the rest of their products to the new Steinberg Licensing system. Nuendo 12 will likely arrive in the next few weeks, almost certainly using Steinberg Licensing.
I am pretty sure there was mention of a new version of HALion in one of the Steinberg Licensing announcements, though I do not have a link to hand. I would expect HALion 7 and a new version of Absolute, at which point these products will move to Steinberg Licensing.
I hope, in time, there will be the ability to move existing licences for products still in maintenance to Steinberg Licensing without a (paid/grace period) update. Such a system is potentially important for WaveLab, which normally goes 18-24 months between major releases and had a paid update late last year. Such a system is even more important for content licences, as these often do not get any sort of paid update.
I have a whole pile of Steinberg licences that I long to transfer to Steinberg Licensing so that I can use them on my Surface Pro 7+ without moving the USB eLicenser from my main system. Dorico 4 is on Steinberg Licensing already. I expect Nuendo 12 to be available soon. However, that leaves VST Connect Pro, WaveLab Pro, Absolute, SpectraLayers Pro, Iconica and numerous add-on licences still to transition. In total, I have 25 licences still to transition to Steinberg Licensing!