I think that Krishnamurti's warning against "becoming" (because it involves strife) is an ironic statement. To ambitiously become something else is really to go from one fixed state of being to another, more ideal, fixed state of being. Once one has achieved the ideal fixed state, he tries to hold onto it, not to let it become something else--until another contrasting ideal comes along. In that case, "not becoming is strife."
We are a part of all we have met, so as they become, we become. If that is destiny then so be it.