My thought is this: The passive purgations are intrinsically interior desolations and trials, and are not touched by the externals of an Order or a Rule. No founder can initiate a dark night, and none can complete it. The work is interior, is of God, and is relieved only by God directly and immediately.
These discussions are becoming increasingly complicated

Passive purgation is definitely initiated and completed by God. In fact it is necessary because no matter what we do we can never attain to that absolute transformation of union with God unless God himself perfects the work of purification through the Dark Night. But the “externals” are used by God to place you in this stage. God uses the events, circumstances, personality make-up, dispositions, etc. of a person to effect the night. All these are the "ingredients " needed to effect the Night. Our humanity is the stage needed to play out this transformation. I agree that it is not the founder or the rule that effects it, it is God.
ACTIVE purification however is dependent on the individual. One chooses to mortify her senses, intellect, memory and will to cooperate with grace and the work of God. the initiative is ours. There was never a question of who finishes the job! And one’s choices heavily depend or are influenced by one’s spirituality or spiritual charism. We choose to enter this Night of the senses. St. John of the Cross has a formula for entering the night in his Ascent of Mount Carmel chapter 13 (Collected works by Kieran & Kavanaugh). This was his Carmelite Spirituality. Once the experience of the night begins , one is no longer talking about "is this Carmelite? is this Franciscan? Is this …
I think we will definitely fall into the mistake you are talking about if you separate these holy men and women, founders and foundresses, from Christ himself. But it should not be the case. The reason why Catholics honor these Saints is because we can learn from their example of courage, faith, sacrifices how it is t follow Christ. They exemplify Christ to us- they are not Christ- but God himself in His Providence chose them to teach us how to live the Gospel truths. All Rules and all spiritualities ultimately point to Christ. We are members of the ONE Body but with particular parts to play.
We may never come to an agreement about this. It is not really important I think that we see it the same way. You have your spirituality and I have mine. A typical example of what we’ve been discussing!