Abilities first roll whether they land or not (regardless, you want to be hit-capped). Then they roll whether they crit.
2/2 [Primal Fury] causes your Combo-Point Generator Critical Strikes to grant an additional combo-point.
The minimum amount of abilities you would have to cast in order to gain 5CP is
three (two Criticals and one either-or). That leaves you with 4 favorable outcomes and 4 unfavorable ones. Then you calculate the probability of having a favorable scenario occur which is given by the sum of probabilities of an individual favorable scenario occurring. In other words, the probability of landing 3 Critical Strikes and the probability of landing 2 Critical Strikes and 1 Hit (accounting for all 3 variations thereof).
https://i.imgur.com/7yZIk7o.png