I’m not sure to whom or where the first dispensations from the norm of celibacy for Catholic ordination of former Anglican and former Protestant clergy were granted, but I know that popes going back at least to Pope Pius XII have granted these dispensations fairly routinely going back at least to the 1950’s. I first learned of a former Lutheran minister who had received ordination as a Catholic priest of the Diocese of Raleigh in the 1950’s while stationed at Camp Lejeune in 1983-1984. However, the numbers of such priests were very small and their congregations typically did not come into the Catholic Church with them. This generally happened fairly discretely, with the married priests not serving in parish ministry.But the emerging European doctrine of the 16th and 17th centuries, cuius regio, eius religio, implies that Protestantism was adopted by all affected states, whether Anglophone or Germanophone, for a mixture of theologcal and political motives. Certainly Henry VIII was able to rely on theological as well as political positions among the political and ecclesial establishment to justify the break with Rome. I would say that the idea that Anglicans are "more Catholic" than other Protestants reflects a misunderstanding in Rome.
Note that this accommodation extends to married former clergy of any Protestant denomination — not just Lutherans. When I last visited St. Meinrad Archabbey, its seminary had two married former Baptist ministers studying for ordination for the Diocese of Little Rock. (The magisterium of the Catholic Church does not consider the Anglican Communion to be a Protestant body, even though Protestant influences gained substantial traction therein after the time of separation, because the cause of the schism of the Church of England was political rather than theological. This probably also applies to the so-called “continuing Anglican” bodies.)
In the late 1970’s, the decision of the Episcopal Church – U. S. A. (ECUSA), now known as The Episcopal Church (TEC), to ordain women brought two dramatic changes in the situation: first, a sudden swell cases of former clergy of ECUSA (TEC), numbering in the hundreds, seeking dispensations from celibacy to permit their ordination in the Catholic Church in the dioceses of the United States and, second, a number of requests for congregations coming with their pastors to retain their familiar Anglican liturgy within the Catholic Church. Pope John Paul II responded to this situation by establishing the so-called “pastoral provision” in 1980 (1) to facilitate the processing of the large volume of requests for dispensations from the norm of celibacy for former ECUSA (TEC) clergy seeking ordination in the Catholic Church and (2) to allow erection of personal parishes and quasi-parishes that would use liturgical books adapted from the Book of Common Prayer where there were enough laity to do so.This would support my thinking that Fr Dwight Longenecker, although a married former Church of England priest, was not ordained in the Catholic Church via the Pastoral Provision but via the normal channel. Certainly he makes no special case for his Anglican history and clearly treats Anglicanism as a call to a life of faith that is fully expressed in the Catholic Church -- but Lutherans, Presbyterians, Baptists, and all others receive the same call and respond to it fully in the same way.
Note that the “pastoral provision” applies only to former Anglican clergy in the United States. The Vatican continues to process petitions for dispensations from the norm of clerical celibacy for former Anglican clergy in any other country and for all former Protestant ministers, including those in the United States, through “normal channels” (directly from the respective diocesan bishop to the Vatican) with no involvement of the Office of the Pastoral Provision whatsoever. What’s interesting is that the erection of the Personal Ordinariate of the Chair of St. Peter actually created an exception to the so-called “pastoral provision” — dispensations from the norm of celibacy for its married former Anglican clergy actually go through normal channels rather than through the Office of the Pastoral Provision. Or, alternatively, one could construe that each ordinariate performs the functions of the Office of the Pastoral Provision for its own candidates.
And yes, the fact that “celibate former CofE priests had an easier time” is not a particular surprise. Fundamentally, they did not require dispensations from the norm of celibacy, which is an additional hurdle for married clerics, so their cases did not have to go to the Vatican at all. Additionally, some diocesan bishops probably were less than receptive to married candidates for ordination for various reasons — fear of rejection by other clergy, fear of rejection by the laity, uncertainty of acceptance by the Vatican, specific details of individual cases, and their own prejudices all being potential factors. I also have heard that the Vatican did limit the number of dispensations from the norm of celibacy to two per diocese, at least until they could assess how the Catholic laity and other Catholic clergy would receive them. As a result, some — perhaps many — married former Anglican and former Protestant clergy undoubtedly have had to shop around for a diocese with a bishop who would accept them as candidates for ordination.While some visitors disagree with my sympathy for Abp Garcia-Siller and his position that Anglicans under the Pastoral Provision and Anglicanorum coetibus want to be "not unique but separate", I think the archbishop is identifying a potential hurdle that adds confusion to the overall question of how the Church welcomes all former Protestants.
By the way, a few celibate former Anglican priests are now Roman Catholic bishops. Bishop Allan Hopes, who served as the apostolic delegate for the erection of the Personal Ordinariate of Our Lady of Walsingham while an auxiliary bishop of the Archdiocese of Westminster and is now the diocesan bishop of the Diocese of East Anglia, is of particular significance in the context of the ordinariates.