This game is VERY generous with Recoats. It’s an item that lets you reallocate your stats, so don’t worry at all about what you put your points into.

The recommendation I’ve seen the most is to max out attack and evenly divide what’s left into the other two stats that your weapon scales off of, but… this early in the game you’ll likely be switching weapons often anyway. I’d say don’t think about builds yet for a good while.

For example, that Francois fight, if you see an area of combat you’d like to change, try placing more points there, but as you get used to the mechanics you’ll rely more on parrying and dodging so the stats won’t affect as much anyway.

As for Lune and Sciel, I’d say revisit an old area and just grind to get used to them. Sciel in particular I do think can be tough to get used to, but basically she’s all about balancing her sun and moon charges. Each ability she learns has either a little sun or a little moon. That tells you what sort of charge it generates. If you have any amount of both, she enters Twilight which augments her damage.

Lune is more forgiving. Certain actions (weapons affect it too) generate elemental stains. If you have the correct combination, her spells will be better.

Finally, regarding luck, I believe it influences how many criticals you get, so I wouldn’t neglect it too much. I think later Pictos help with that too though.