The way I see it, the roles are distributed as such amongst the cast:
Mirana Kamaria - Melee / mid-range combat specialist, infiltrator. Focused on mobility.
Esfir - True support, quick-response melee unit. Balanced.
Alice Aegis - Long-range combat specialist, artillery. Focused on offense.
Toro Suzuku - Mid-range combat specialist, offensive support. Focused on sabotage.
Charm-4 - Long-range combat specialist, sniper. Focused on offense.
Komei Yasunova - Melee combat specialist, warrior. Focused on offense.
Eunike - Melee combat specialist, offensive support. Balanced.
Yulia Nazarova - Melee combat specialist, warrior. Focused on offense.
Rika Kamaria - True support, long-range combat unit. Balanced.
This is by no means a complete summary or a guideline, but rather my interpretation of what role each team member would fit the best based on their equipment with a slight help from the description of their fighting style. Based on this, the team does have a slight focus on melee specialists, but I think that the overlap is tolerable. Of course, the end decision is in R-9's hands.