This question would seem to depend on the first dispute we mentioned above, whether, after the fact, according to Hillel one can fulfill the requirement to eat maror by itself without matza. If, after the fact, one has already fulfilled the requirement by eating the maror by itself, that would mean that by the time one gets to korekh, one has already fulfilled the commandment, and eating the korekh at that time is merely a remembrance of the Temple practice, and there is no additional fulfillment of maror consumption.
However, if according to Hillel one does not fulfill the ordinance of eating maror by itself, the eating of the korekh fulfills the rabbinic decree of maror. This latter approach is suggested by a number of Acharonim (Vilna Gaon, Bei’ur ha-Gra 475:1; s.v. u-mi’she’beirekh; Peri Chadash, ibid., s.v. ve-khorekhah, and others), namely that the korekh is not only a remembrance of the Temple practice, but is the main element of fulfilling the ordinance (by rabbinic decree) according to Hillel.
This question, though, depends on another question. As cited above, there is a dispute among Rishonim if Hillel wrapped only the matza and maror together, or whether he added these to the Pesach sacrifice. If Hillel also included the Pesach sacrifice, then, in our times, where there is no Pesach sacrifice, the entire wrapping of the items together loses its real significance.
Thus one can say that even if at the time of the Temple there was an obligation to combine the two, and eating maror by itself would have been of no value according to Hillel, nowadays, where there is no Pesach sacrifice, the commandment of eating maror, which is only by rabbinic decree, need not require be combined with matza, and it is possible to fulfill one’s obligation by eating the maror alone even according to Hillel. It follows that as we have the custom of eating maror by itself out of concern for the view of the Sages, we are thereby fulfilling our obligation of eating maror even according to Hillel, and when we eat the two together it is only a remembrance of the Temple practice, but not a fulfillment of the obligation to eat maror. That is what the Bach (475, s.v. u-ma she-katav ve’achar kakh noteil) wrote, that nowadays where we have no Pesach sacrifice one is unable to fulfill the korekh properly, and that is why we fulfill the obligation to eat maror by eating it by itself, and the korekh is only as a remembrance. That is also the view of the Maharal (Gevurot Hashem, 63), and that is the view accepted by the Acharonim.
Reciting “A Remembrance of the Temple practice according to Hillel”
The Shulchan Arukh (475:1) writes:
Once he recited the blessing on the matza he should not be distracted by anything which is not part of the meal until he eats this combination, so that the blessing of matza and that of maror will apply to this combination as well. In other words, one should not speak between starting to eat the matza until finishing korekh (except for those matters which pertain to the eating). The source of this is the Tur (475) in the name of the Sefer ha-Manhig (Laws of Pesach, 84). They explain that since according to Hillel it is a commandment to eat matza and maror together, when reciting the blessings of matza and of maror one must keep in mind to include korekh in those blessings.
This question is also dependent on the dispute among Acharonim mentioned above. If korekh is the main aspect of eating maror according to Hillel, it is clear that one may not interrupt with conversation between eating the maror and eating the korekh, for that would be an interruption between the blessing and the performance of the commandment. That was also what the Vilna Gaon and Peri Chadash wrote, as quoted above. However, if korekh is only as a remembrance of the Temple practice, it is only a preferred practice that one should not speak between the blessing and korekh, just as, in the view of Hillel, at the time of the Temple one was forbidden to speak between the blessing and the korekh, but that is not required by law. That indeed emerges from the words of the Manhig and of the Tur, who write that this is “most preferable,” as the Bach (475, s.v. u-ma she-katav ve-khatav od), based on his view above, wrote.