So, Lloyd costumes. I think they should have a gimmick where the costume Lloyd wears changes his Boxing Ring title, since in Tales Titles are an actual feature that impact gameplay. I think EX Gems would be more than enough, having his costume change how he plays would be completely insane, so I'll let that slide.
Default (Eternal Swordsman) - Colette Colors (Peeping Tom) - Genis/Sheena Colors (Gourmet King/Gentle Idealist) - Kratos Colors (Sword of Swords) - Pirate Costume (Arrgh, Me Hearties) - Beach Costume (Beach Boy) - Noble Costume (Nobleman) - Samurai Costume (Unrivaled Blade).
Might've posted this before, sorry if I have, since I've had this idea for a while.
Also, I could pick 11 Symphonia Songs easily (without touching the sequel, too). Full Force, Like a Glint of Light, Keen-Edged Blade, Keep Your Guard Up!, Fatalize, The Law of the Battle, Fighting of the Spirit, Beat the Angel, The End of a Thought, It Can Waver and Fight, and Final Destination (do not look up those last three songs, they are spoilers if you haven't gotten to the part where they play) if we only do battle themes (The Struggle to Survive is probably the weakest of them). If we have themes outside of battles, The Edge of Nowhere, Search a Seal, a new mix of Lloyd's theme, The Land of Sylvarant, the second world map theme (conscious of spoilers that are in the title), and that's just scratching the surface.
That being said, if Namco is more generous with songs, I could see 17 songs: 11 from Symphonia, and 6 from other titles in the franchise (Phantasia, Abyss, Vesperia, Xillia, and Berseria, for example). And it's unlikely that if we only get 11, all 11 of them will come from Symphonia, unless Sakurai doesn't do for Tales what he did for Persona.