Easy one first:
But the simple answer is, you join a ZWave stick the same as any other ZWave device. Put Hubitat into pairing (Inclusion) and get the ZWave stick to pair. For Aeon, just click the big button once.
As to including ONLY with a ZStick and then having the hub see the device.. well.. that's somewhat automatic, but incomplete.
When the ZStick is doing the Inclusion, it FIRST converses with the SIS/SUC (the Hubitat Hub) to get the next Node Number... which it then passes on to the target device. When complete, the Hub knows the Node was assigned but will not have initialized yet. On the ZWave Details page, a Device should appear with a Discover button. No Automatic Assignment of driver occurs using this method.