There is one detail:

The number of points in properties.lsx for NumStartingAbilityPoints must match what it would cost to allocate that level.

So if you want to have 2 lvl 1 abilities and 1 lvl 2 abilit you need to set NumStartingAbilityPoints to 5, not 5.
The reason is (by simluation of selecting points in the character creation screen):
The first lvl 1 ability cost 1 point.
The second lvl 1 ability costs 1 point (total 2 points)
The third skills lvl 1 costs 1 point (total 3 points)
The third skills lvl 2 costs 2 points (total 5 points)

I.e. The final number to have in the properties.lsx is:
a*1 + b*3 + c*6 + d*10 + e*15
Where a = # of lvl 1 abilities, b = # of lvl 2 abilities, c = # of lvl 3 abilities, d = # of lvl 4 abilities and e = # of lvl 5 abilities
So to have 2 lvl 5 abilities and nothing else, NumStartingAbilityPoints should be 30



You might also want to ensure that the values of all the "handle"-attributes are unique, i did it by simply modifiying the last letter/digit to be something else for my custom class. Not sure if it was required but it worked.