A1. The amount of members you can add in the group really depends on your progress in the game. Normally as you play the game more and more you get more amount of members to add in group. It expands from 2 and really goes up to full on 8 members for the game. As you get even more members in your group, you can send more members to missions. It is more beneficial because you can get even more rewards from the missions and some objectives.