Nigel,
Oxygen seemed very powerful, but ....
These are answers from Oxygen:
>> I wanted to know if Oxygen is fully compatible with Toolset, now that Toolset is fully oriented to Gutenberg?
You can see a list of the compatible Toolset fields here: versteckter Link.
>> I would also like to know if Oxygen is compatible with the toolset repeating elements?
Unfortunately, there's no built-in compatibility with Toolset's Repeating Fields.
>> In case the answer is negative, will you soon incorporate these functionalities in Oxygen?
Unfortunately, I'm not able to comment on future development plans for Oxygen. However, if you would like to see additional Toolset compatibility, please open a feature request here: versteckter Link.
>> Is it fully compatible with WPML?
Unfortunately, Oxygen isn't integrated with any translation plugins: versteckter Link. However, we do have a number of customers successfully using Polylang with Oxygen.
>> I would also like to know if Oxygen is 100% compatible with Yoast SEO text analyzer?
Unfortunately, there is a known issue where content rendered using an Oxygen template can't be analysed. We have a bug report open for this here: versteckter Link. A workaround is to edit the post content directly (don't use a template and click "Edit with Oxygen" directly on the post page) and then insert the content dynamically so that it can be analysed.
Rank Math is another popular choice. One of our users has written a plugin to allow Rank Math to work with Oxygen: https://wordpress.org/plugins/wpdevdesign-rankmath-integration-for-oxygen/.
>> Does Oxygen have support to add special semi-transparent separator in sections like DIVI?
I'm not sure what you mean by this, please can you send me a link to the Divi documentation for this feature so that I can take a look?
>> Does Oxygen have an icon library to be placed anywhere?
Please can you explain what you mean by an icon library? Oxygen has an Icon element that uses Font Awesome and Linearicons. You can add additional icon sets: versteckter Link.
Too bad, it would have been nice....