I really love this game so far. Seriously, this game has a ton of personality and is really enjoyable in general. I especially like all the family characters. I do have a few ideas for feedback if you're interested, because I would love to see this game get even better.
-I think the diving minigame would drag on less if it ended when you grabbed the last shell. Or when you grab a pearl at the end. But having to swim to the end to get the shells and back to the boat is quite a grind.
-There's a few grammatical errors, but the writing is still very good and shows a lot of personality. I think having a native English speaker go over the script might help this, but it's not a huge problem.
-You asked about mission feedback. Personally, I did not even know there was a "main mission" until I read the guide. I think it could be helpful to have a quest log (or something similar), at least for the main mission.
-At times, I feel the game lacks focus in general. For example, that dungeon crawling minigame on the computer felt like way too much development time was spent on it. Overall, Paradise Beach feels like a game that is very wide, but without a satisfying level of depth in the "adult game" areas. That could easily be attributed to being early in development though. But I think it would be good to focus on going more in-depth with fewer characters at the game's current stage.
This game kind of reminds me of Town of Passion and Bones' Tales: The Manor, and I really don't think it would hurt to emulate RPGmaker dating sim games like that with this project. I think focusing on the family of girls for a few updates would be a great foundation, because that's really what made me like this game. Once you have a few events for each girl, you could tie in their progress to the main quest or pearl diving. But personally, I think the relationships with the characters are way more important for an adult game than its missions and gameplay. I think in this genre, the missions should mostly be a way to advance the relationships.
Anyway, all this stuff is my opinion, and this project will still be great if you don't do any of this stuff. Good luck with your game!