1.
Force Field doesn't increase your Defense. It increases your Toughness save. Since you Con is 14 (+2) the max ranks you can have in Force Field (without trade-offs) is 8 (for a total of +10).
2.
Skill points are 4 Ranks/PP, so by spending 11 PPs you get 44 ranks (not 42).
3.
If you want the Water Control base power to be Dynamic as well that costs an additional PP, bringing the cost up to 61 PPs total for the array.
Also, the total cost for your powers looks to be
Immunity: 13 Ranks [13pp]
Immortality: 1 Rank [5pp]
Super-Sensors: 2 Ranks [2pp]
Water Control 20 Ranks [40pp] Dynamic [20pp AP powers]
= 80 PPs
4.
Did you only want 1 rank of Knockback (it is a ranked feat, not an Extra)? You could have quite a few more ranks in the array slow if you wanted.
5.
We have not allowed any damaging effects to be bought down from instant duration thus far, and I am inclined to stick with that here.