You can realize this with the MultiSqueeze Plugin of ours to create a second player with a different output. However, you need to decide which output you want to use for each. If you have active speakers, you need a DAC HAT and can use the audio jack or HDMI output of the Pi if supported.
If you want to use passive speakers, you need an Amp HAT. However, we only recommend using one output for one Pi with Amp HATs. There are some DIY guides on splitting the outputs, though.
You can buy one license for your whole system, but our development is supported by license so we appreciate all purchases.
It really depends on what you want from your amp bundle. The JB amp has an infrared receiver included in the package to solder yourself and use for control. Otherwise there are some more differences you can check out in our comparison chart for Amp HATs