First off, if you're keeping the culture split, it'd probably be better to set the Iberian culture divergence dates back to 900 so they fit that better (except for Andalusian if you're keeping that one separate).

I also noticed that the Aragonese culture is set as uninvolved in the struggle when starting the game in 867, though it doesn't seem to be back to involved upon its creation. There are two ways this can be made more consistent with the others - first, that bit could simply be removed from the game_start on_action. Alternatively, this could also be applied to the other not-yet-present cultures (including Portuguese in 1066) with the condition that these cultures are re-added once they are created by in-game decisions/events.

Also, the Suebi culture is not currently involved in the struggle, and it should probably be added since it does have the Iberian heritage. Maybe there could also be a few counties of it, like you did with the Gepids (if you think it's likely there'd be any remaining by 867, anyways). But even without doing that, it should probably still be in the struggle list in case somebody wants to do a "The Last Suebi" run with a custom character or something.

Yeah, there's quite a bit of work being done on Iberia for v4.2, although it's since become a more general update with some map improvements in other areas and some new religions.

Currently I have a Visigothic/Andalusian split in 867, with the rest of the cultures appearing with the Visigothic split event.

Aragonese being missing in 867 is due to a superfluous on_action PDX added; it's actually present in the struggle file itself, and I've since replaced that on_action with something else so Aragonese will be back in the next update. I shall indeed add Suebi also, and have a playable Suebi in 867.

Thank you for your feedback - it is appreciated.

FYI, I did plan to update the Iberia bookmark map screen but haven't been able to do so yet, so it'll just have to wait until 4.3 or a later update. It's only a cosmetic issue, but it's time-consuming artwork that I have to wait for someone else to do, and they've got Covid.