Gunner is big and brawny so I'm going to say:

Endurance: 3
Speed: 3
Strength: 4

Serena I'm thinking more so:

Endurance: 4
Speed: 3
Strength: 3

Because I think that would be interesting.

Finally, Rae:

Control: 2
Power: 5
Endurance: 3

And then, Finn:

Endurance: 100
Speed: 100
Strength: 100
;P