Seeing how Inkopolis Walker (the untranslated artbook looking like the Inkopolis magazine from Octo Expansion) show an Octoling's growth cycle (kind of disappointing really, they had a great opportunity to make the Octoling more unique than the other Octarians in the other way). So it was shown that even Octolings start as cut-off tentacles, but that's not the only way that Octolings can start life as. It's also very unreliable since for one, the genetic material would be identical to the host and secondly, there's no guarantee that the tentacle would grow into an Octoling, as we see many other Octarians who are presumably adults but aren't Octolings. So here's the conclusion I came up with, while Octolings can come from cut-off tentacles, no genetic variation can occur while an Octoling who hatches from an egg is guaranteed to have genetic variation. The guaranteed way to have Octolings is through sexual reproduction that a male and a female Octoling must perform, because a cut-off tentacle have more chances to develop into one of other Octarian subspecies than Octolings. This actually explains why enemy Octolings look identical to one another with no skin tone variation, those Octolings started out as cut-off tentacles and comparing to the Octoling population in Inkopolis, they are very few. I know that the only enemy Octolings that you fight are elite, but who's to say there isn't a female Octoling donating her tentacles against her will? So my conclusion is that playable Octolings hatch from eggs while enemy Octolings start as cut-off tentacles. This could be why the enemy Octolings don't have a pattern on their tentacles, as if a tentacle is cut off from a host, the pattern disappears.