I will give a link to an online pdf that I have found helpful.
The title is : "Criswell Theological Review 4.1 (1989) 77-95.
Copyright © 1989 by The Criswell College. Cited with permission.
PAUL AND THE MINISTRY OF
RECONCILIATION IN 2 COR 5:11-6:2
DAVID L. TURNER
Grand Rapids Baptist Seminary
It’s a careful exegesis and well worth reading. Here is a short excerpt, followed by the link:
Excerpt: (and yes, the emphasis is mine :-))
5:19 further explains the thought of 5:18. Two other questions confront the exegete of this verse. First, should the prepositional phrase e]n Xrist&? be understood adverbially (“God was reconciling in Christ,” NIV) or adjectivally (“God-in-Christ was reconciling,” KJV, NASB)? The first option is preferable due to the usual usage of prepositional phrases as adverbs, not adjectives. Further, Paul’s emphasis is not upon incarnation but upon reconciliation, and it is his habit to mention Christ as the means of reconciliation (2 Cor 5:18; Rom 5:10; Col 1:20). The second question concerns the periphrastic verbal construction h#n . . . katalla<sswn (imperfect plus present participle). One wonders why the simple finite verb was not used, and also why the progressive aktionsart rather than the aorist (as in v 18) appears. Perhaps the best answer is that Paul wished to emphasize here the element of contingency in the ongoing process of reconciliation through the ministry of the gospel. It is noteworthy that the middle clause of v 19, “not counting their sins against them,” also uses a progressive tense (logizo<menoj, present participle) to describe God’s reconciling action. Although there is an historic, objective sense in which reconciliation was finished at the cross, there is also the subjective actualization of that objective truth as the gospel is preached and people believe.
End
Link: https://faculty.gordon.edu/hu/bi/ted_hildebrandt/ntesources/ntarticles/ctr-nt/turner-2cor5-ctr.pdf
Now here is the section concerning the Cosmic effect of the reconciliation in process:
Paul’s statement in v 19 is that in Christ God was reconciling “the world” (cf. Rom 11:15) to himself, not “us” as in v 18. While some take the world as equivalent to “all” (people) in 5:14-15,35 it is more likely that a cosmic meaning is intended. Though people are primarily in mind (note the middle clause of the verse, “not counting their trespasses against them,”) Paul’s thought cannot be limited merely to human beings. Paul has been speaking of the new creation in Christ as superseding the old creation ruined by Adam’s fall (5:17). Thus it is likely that he does not mean merely all people (believers?), or even the Gentiles as opposed to merely Israel (as in Rom 11:15), but rather the universe as a whole. “All things” are in the process of being reconciled through the cross of Christ. The effects of the second Adam’s obedience can be no less than the effects of the first Adam’s disobedience. As Adam’s disobedience wreaked havoc throughout the entire created order, so Christ’s obedience will ultimately harmonize the universe in the new heavens and new earth. The entire ko<smoj will ultimately be at peace with God due to Christ’s redemptive mediacy (cf. Rom 8:18-21; Eph 1:10; Phil 2:9-11; Col l:20). This is not to be confused with soteric universalism, since many will only bow the knee grudgingly. However, recognition of a sort of cosmic universalism is necessary if we are to grasp the glorious comprehensiveness of Christ’s work of redemption.
Wow!
Though from my humble opinion, the reconciliation has happened. The acceptance on humans part (repentance) is an on going affair. But it really does not matter how you want to slice it or say it. 
