I'd actually think Scarlet Nexus's system of your party members augments the moves you are capable of doing might be a good mechanic to implement. Because with multiple playable characters they kinda all have to feel fun/good to play and you'd need to make them synergize with the whole team.
Barret and Aerith as the "ranged characters" kinda sucked in FF7R
Barret and Aerith as the "ranged characters" kinda sucked in FF7R