First let me start by saying welcome to Science (its what Wissenschaft literally means). Your joining the ranks of the most OP organization of the game. We have lots of speed and, with the process, toughness as well.
Second, that Legacy team is honestly too fragile. Legacy is as close as indestructible as this game gets, the best way to beat it is to kill the rest of the wiss team. And your team is full of fragile characters. Yes, a process shield helps a lot but you lack a frontline to help Legacy in combat. Legacy 90 only really works by using the org. advantage manipulation to save points. But thats not officially out yet in english so never mind. Best to stick with Legacy 75 and use the process.
Org. Adv. The process
Legacy Of Solomon (Valeria Strauss)
This list gives you a tough frontline by put shield on 2 of your fighters. Use Rayne(w/ process shield) to protect Lorenzo and Hiro so they can save AP for charges. Cordelia is always useful and can eat alive most Damage Resistance (DR) characters by herself. Use Sophia to buff Lorenzo and give extra AP to legacy so he can always use is special dodge.
However, playing Legacy doesn't really give you what you originally asked for, a 60/40 Melee/Shooting team.
Org. Adv. The Process | Team Card: Assault Group
Grimorium Verum(Steiner Wenzel)
Fate or Sophia
This list provides plenty of firepower. Half the team can shoot and they are all powerful shots. XII can use a process Haste to shoot twice every turn and Cordelia is anti-armor. Don't underestimate Grim's ranged shot, Even if he is inaccurate, at 4AP it still does base 12 damage. Its an attack that enemies must dodge.
Note - read Fate's stats here: http://cipher-studios.com/AnimaBB/index.php?topic=5638.0
Fate isn't out yet but feel free to proxy her with Sophia or another mini. I honestly think shes better for this list than Sophia but they both have their uses. Sophia can provide buffs to the assault group as well as Grim, but Grim is very inaccurate without constant buffs.
Fate has several advantages over Sophia when played with Grim. First, just taking Fate provides a constant +2 attack buff to Grim as long as she remains on the table. This means that Grim suddenly has an 8/8 -2 armor charge. Fate can heal for Grim and combine with Steiner, Grim can heal an amazing 10 LP every turn if you spend the AP to do so. Last but not least, Fate can give AP to Grim which means he can spam his AoE attack more often or simply basic Attack and Heal every turn.
Simply put, Fate takes Grim,a somewhat mediocre Damage Resistnace character for his cost, and turns him into a God on the battle field. Grim gains the accuracy to be an effective threat as well as being one of the most incredible tanks in the game with a possible 10 LP a turn healing.
Overall, this list gives a lot of speed (Assault Group), toughness (Grim and process shields), and plenty of firepower.
Its a damn good list that should do well against just about anyone else with good tactics. Yes, I've seen Grim crush Damien 1 vs 1 even though Damien is a direct counter to DR characters. Not only that, but Grim can just heal himself back UP afterwards.
Note: XII can use both his innate process and the Org. Adv. Process at the same time. So you can pick two positive status to place on him. Remember that, its big part of what makes XII so great. I have seen XII go from close to death to ending the game at full health.
Sophia was suppose to be sold in stores as part of a pack with other wanderer characters at a discount.
You can still order her from Cypher Studio: https://cipher-studios.com/store/index.php?main_page=product_info&cPath=1_18&products_id=37&zenid=063bdb47b48fc38697e7bb99995de110