So @deandddd has hit upon my line of thinking with regards to multiple orifices. I think this is the key that everyone has been missing in these discussions as it makes the most sense with the previously discussed "thin" polar crusts.
Furthermore I think the concept and etymology of the word "ABYSS" is very important:
I think it is plausible to consider that the word abyss did not mean that to which we ascribe it today. It seems as though "abyss" was more of a conduit or passage instead of a place of seemingly infinite depth or a pit as is used today...
Can we dig into the root of "abyss" further? What was this word pre-Greek "abyssos" and the Hebrew "tehom"? They allude to some things in that article, but what other options do we have for seeking true meaning an intent? Sanskrit? Cuneiform iterations? Others?