Not particularly. Phantom does use a Melee, Ranged and Technique weapon, but it's not focused around switching compared to the Hero and can stick to one weapon. Heck, it's a bit infamous for being a much better Force/Techter for dealing damage and evading and the amount of damage it does with Techniques and it's Melee attack are very much stronger than it's damage with Katana and Assault Rifle. It's not that those weapons are bad for Phantom, but the Rod and Techniques just do so much more damage.
For stages, the most likely stage would be travelling around the outside of the ships of the ARKS Fleet. The Guardian and Matoi are members of ARKS and your main Hub is in an ARK ship. However, you get alot of sight-seeing on the actual ARKs fleet itself and for a stage, you can have the players fight outside the ships of the ARKS Fleet, then transport them to the outside of the different planets of PSO2, like Naverius and Lilipa. They can also transport to the ARKS Mothership and witness it be corrupted by Luther the Fallen as an idea.
As for music, Behold! The Main Theme of Phantasy Star Online 2, The Whole New World
Pretty much the main theme for not just being on the first Intro sequence, but for being used as the climatic final touch of the majority of the Story Bosses. Here's a good case example that includes an old favourite theme of Phantasy Star RPG fans.
As for other music, Phantasy Star Online 2 has alot from ambient tracks that switch to battle tracks when an enemy appears:
To Normal Boss tracks, with most Bosses you encounter in areas having their own theme sorta like Monster Hunter:
To the Urgent and Story Quest Boss tracks:
To some remixes of Phantasy Star RPG and PSO tracks like the one track above:
To the Guardian's own theme in Episode 5 and 6:
To Idol and Concert music:
To the Opening Themes that aren't the Main theme:
To ****ing Leygender! Because it deserves to have it's own Spoiler Slot and Mention!
And there we go People! So many Phantasy Star Online 2 music tracks for you to check out if Phantasy Star gets a character in Smash. And if you really like them, there's still plenty of music I didn't show that you can find on Youtube. At the very least, listen to frickin' Leygender. To me, that music track alone is worth a Phantasy Star character like Ezio is worth it for Venice Rooftops. But still, try to give all the tracks a good listen, even the Idol and Concert music.
Now if you excuse me, after doing this post: