Weaver Xtreme is free like Weaver II was
The “Plus” plugin is a purchased option like “pro” was but the licensing will be different
https://forum.weavertheme.com/discussion/10797/weaver-ii-pro-and-weaver-xtra#Item_6
Instead of having a different theme (weaver II pro was a different them that Weaver II even is using the same base options), With Xtreme, you have a base free theme, and you add the advanced features with a Plugin (Plus) which makes it easier to maintain and update.
Joy has finalized her converter you can try it out on her page.
https://joyreynolds.com/downloads/weaving-3-ways/
Child theme are a WordPress feature they are available on any theme including Xtreme.
The theme is available for download from its site (I gave you the link in the previous post https://weavertheme.com/weaver-xtreme/ ). This is until it passes review at www.ads-software.com, then it will be available there.
You can create a test WordPress installation in a sub folder of your existing site and test it there. You can also clone the content of your site in that test site so you can really see it in action on your actual content.
Once you install and activate Xtreme, you also need to install the Weaver X Theme support plugin.
While it is in Beta, you can also download and install the plus plugin for free from the Xtreme site.