The rule of "you must submit your own ships" exists so that you don't claim ownership of other people's ships. Given that you will instead be submitting the ships for other players, who can't due to circumstances, I would say is entirely okay. Thank you for taking the time to be cordial and clear with your message, and I look forward to clarifying further as necessary.
Additionally, I would also say that due to the same circumstances you can submit SOtD submissions, so long as it's credited to the proper author.
Lastly I do have to mention that when you are painting ships and submitting them to design contests or for SOtD, they must be entirely of your own creation or collaboration. Though Athyranphy is a pretty ship, it is actually a modified version of a ship I have made known as the Executor, which is a built-in ship you can find in the campaign. As such it would not be eligible for a design contest or SOtD submission.