Hello all, just a new player question here, how do you arrange girls in the party 1 to 4

Do you all arrange by

1)Spreading their total power evenly?
2)According to their ability skill(eg. Total def, atk, solar burst, activation rate)?
3)Movement speed?
4)The * of the girls?


And can i know it is compulsory that a party consisting of 5 girls must have at least Pierce, Magic, Slash, Strike?