Selichot, Prayer And Tachnun

It is a machlokes among the poskim of the previous generation (cited in Dirshu Mishna Berura siman 602,) if a bris falls out on one of the days of selichot if the tachnun of the selichot is omitted as well or not.  [There are some technichal details if the selichot is done before nets when it is not the optimal time to do the bris, then there is more room to say one should recite the tachnun, but assuming a case where the selichot is being recited after netz, that is where the debate begins.]  The Shevet Halevi (volume 4 #54) brings proof from the halacha of erev Rosh Hashana where we don't say tachnun in shachris, yet we still say tachnun as part of selichot.  We see that the tachnun is part of the selichot, distinct from tefillah.  [However, this law  of erev Rosh Hashana is not agreed by all either, some hold in fact the tachnun should be omitted.]
I was wondering if this debate may hings upon the chakirah of Rav Yehuda Deri (Avnei Azer volume 5 siman 6) if selichot is a form of teshuva or a form of prayer.  He brings a proof from the Rambam Law of Teshuva (2:6) אַף עַל פִּי שֶׁהַתְּשׁוּבָה וְהַצְּעָקָה יָפָה לָעוֹלָם. בַּעֲשָׂרָה הַיָּמִים שֶׁבֵּין רֹאשׁ הַשָּׁנָה וְיוֹם הַכִּפּוּרִים הִיא יָפָה בְּיוֹתֵר וּמִתְקַבֶּלֶת הִיא מִיָּד שֶׁנֶּאֱמַר (ישעיה נה ו) "דִּרְשׁוּ ה' בְּהִמָּצְאוֹ".  The Rambam starts with two things, תשובה וצעקה and ends with one, היא יפה and his proof is only for צעקה not for teshuva, so how do we know that teshuva is more readily accepted during the days of repentance?  We see that the צעקה, the selichot of the days of repentance are a way of expressing teshuva, so if the צעקה is accepted that means teshuva is accepted.  However, he leans to say that the selichot recited by Sephardim during the month of Elul are a form of prayer.  (He discusses if this way impact if women should recite selichot.) If we assume like his difference we can suggest that if there is a bris during the month of Elul that the Sephardim should skip the tachnun of the selichot.  One can't bring a proof from Erev Rosh Hashana because over that is a selichot of teshuva as opposed to the selichot of Elul which is a form of prayer.
Halacha l'maaseh someone I know that is Sephardi is getting married during Elul and was wondering about the tachnun in the sheva berachot.  Rav Yitzchak Yisraeli told him that the selichot is a different din and the tachnun shouldn't be omitted.