There were Basque sailors and colonists but Basque isn't automatically the same thing as Navarran.
How is that? Navarreses are basques. So can how they not be the same?
No! WTF!! It makes no sense historically!!!! They seem designed ideas for the Basque provinces, but not for historical Navarra, which has nothing to do.
Navarra had only one port in the Middle Ages (Fuenterrabía), but irrelevant. The Navarrese Company, for example, embarked on Tortosa (Catalonia) to Durazzo, in mercenaries boats. Navarra never threw whaling ships, of course. The Dorretxeak had no defensive importance. In the north, manors were defending other nobles, not from the outside, and had no defensive value compared to the castles of the south. So when Navarra was conquered, Cardinal Cisneros ordered to destroy the castles, dangerous for the invaders, not those buildings without relevance.
Nor was Navarre them stand in colonization, however yes there was most brilliant thinkers (Doctor Navarrus), missionaries (San Francisco Javier), theologians (Bartolomé de Carranza), politicians (Rodrigo Jimenez de Rada), military and engineers (Peter Navarro)... You could have chosen many other fields, no colonization.
And the idea Royal Basque Society is the icing on the cake. A disaster. I hope you rectify.
I mostly agree with you.
Navarra never gave up their aim to recover Alava, Bizkaia and Gipuzkoa from Castille. These two later provinces (Bizkaia and Gipuzkoa) plus Labourd where very deep into fishing and whale hunting. Should Navarra had recovered those lands, they would have probably encourage their naval power. But as they were, as you said, landlocked, their strategy was pretty different.
Navarra should have a more diplomatic aproach, IMHO. They survived surrounded by big powers for a pretty long time. Basque people are very proud of the Kingdom and its deeds, even when it's best time was before EU IV timeframe.
Anyway, as a basque speaker, I do agree with the other forumites: dorretxeak towers is like saying tower-house towers. And as Sanz de Acedo said, they were small castles, better for internoble struggles rather than handling big armies against them. But, I'm ok with giving them a defensive bonus, though. Just change the description.
All in all, I would stand more historical for the first half of the NIs and start with the "what ifs" in the later part.