How to publish an extended version of a Springer journal article on arXiv? Our team successfully participated in a challenge. We are now in the process of describing our approach in a paper. Initially, each team was supposed to write a separate article which would have appeared in a special issue of a journal. Unfortunately, the editor of the issue changed his mind and there aren't enough pages in the issue to cover each team separately. Instead, the organizers are writing an overview paper where each team is allowed to append 3 pages describing their approach. This will result in one paper with ~15 authors.

We sort of anticipated to write more than 3 pages. Therefore, we are thinking about writing a more in-depth article that sort of extends our part in the joint article and publishing it on arXiv.

For the sake of not confusing anyone, let's


call the joint article A. A will be published in a Springer journal
call and the extended version intended for arXiv B


Both articles are written in English and are about the same content. We basically want the content (examples, figures, screenshots, and text if possible) from A to also appear in B.

What do you think is the best option?


Create the B first and refer to it in A? There shouldn't be any problem with blind submissions, only copyright issues 
Submit the A first and publish B later.
Refuse to participate in A since we only have control over 3 of the 14 pages and cannot control what the other teams are contributing to the paper. Instead, only publish B.
For A, I think the introduction should make it clear that each team contributed to a particular part of the document, moreover, each team should have the opportunity to review/comment/improve sections by other teams, this should help address concerns regarding 3, thus, lead us to favour options 1 &amp; 2.

Option 1 appears to be the easiest option, because problems might emerge during option 2: B might have copyright issues (because A was published first and is subject to copyright), and addressing these issues (e.g., perhaps by attributing content in B to A) is likely to be time-consuming.

On this basis, I recommend option 1.