* What is the standard difficulty level for a normal new game ?
Difficulty level = number of uppgrades enemies get in Hp, Tough, Quick & Attack power in the same way you can uppgrade your characters.
At level 10, expect at least an increase of 60%. (Exact values vary depending on the enemy)
* How much damage does a support attack do without combo attack ?
* What spirits do Yumizuka Satsuki and Mecha Hisui get and how much SP does each cost ?
Strike, Alert, Accel, Vigor, Valor, Fury
Bless, Cheer, Faith, Exhaust, Renew, Hope
* My game seems to take up more and more memory space as I play it
I don't have this problem. BMW barely takes any ressources... 20 MB at the title screen & 100 MB on my RAM during a battle, and my save file takes 3 KB.