Tales of Graces F

Alright, I beat the original storyline. Do I continue to the future arc, or is there stuff I should take care of first? I'm not sure if I'll miss anything by going on with the story.

Starting the Future Arc disables a lot of sidequests. When you complete the Future Arc, you get to make a save like after beating the boss and they'll be re-enabled again.
Bonus Dungeon comes after the Future Arc, based on the level of the content. The first floor's boss in the bonus dungeon is level 75 on Normal. You can get a feel for the difficulty of it by going to Lhant and seeing the cutscene and fighting the monster. All the equips you get from post-game events are better than the Future Arc ones too, for the most part.

 Last boss subevent spoilers

After obtaining Pascal's 3 mystic artes, and reaching Lambda, you can go to each Valkines Cryas and fight its guardian. They're level 75, 95, and 110 in the order of appearance, and drop the 2nd best Dagger, Bladerang, and Dualblade. They are required to be defeated to enter the 10th floor of the bonus dungeon. Should be done after Future Arc as well though, so the Future Arc weapons aren't obsolete, and the content isn't too easy. These fights can be difficult due to the sheer strength of each attack.

Just got Pascal. She is my new favorite character.

More tips!
Pascal's first mystic arte can be obtained to the west of Gralesyde from a sub-event by talking to some bandits and beating them. Everyone else gets theirs from main-story events so hers can be easy to miss.
To get Pascal's second mystic arte, you need to see the subevent at Sable Izolle research lab.
To get Pascal's third mystic arte, when you reach Zhavert, at the fork before Sneek Research Institute, go down and you'll get a cutscene.

When you get Shine Field, use it 30 times to unlocked Shine Field Adept, which has Pascal's strongest spell (i.e. highest damage) at the 3rd skill. Not necessarily her best spell, keep in mind, but one of them.