#husayn

Ah, I think that while the Sunni=Protestant / Shi'a=Catholic analogy can kind of work so long as it's understood not to be a one-to-one analogy and that it falls apart the second any nuance is applied to it, I still think it only applies to some of what you said and not to others.

Sunnism definitely does not have a hierarchy the same way that Shi'ism does, and Sunnis definitely don't believe that devotion to the 'Ahl al-Bayt (the family of Muhammad) is an essential duty in the way that Shi'is do, but there is significant overlap between most Sunnis and Shi'is in terms of the other things you mentioned.

Muslims of all kinds have a long history of relic- and saint-veneration, from (Sunni) Mehmed the Conqueror who supposedly had a tooth of Muhammad to Hazratbal, considered one of the holiest (pan-Muslim) shrines in India because it houses a hair from Muhammad's beard. There are also lots of stories about Muslim saints appearing to others in visions to initiate them into esoteric rites (Sufism, primarily a Sunni phenomenon), and many tombs of great scholars or mystics have had mosques built on top of them, often with their own traditional pilgrimage rites to go with them. Salim Chishti, for example, is a Sunni saint of the Chishtiyya order whose tomb is often visited by women seeking to become pregnant; they ask for his intercession by tying a little red ribbon around the fences of the shrine.

Aisha, the widow of Muhammad, leading forces against the Party of ‘Ali, from a 15th century manuscript. Source.

Early Sunnis on Karbala: Sympathetic, but not Pietistic

[T]he historical accounts of the events of the Battle of Karbala and its aftermath are transmitted in the earliest Sunni sources by Sunni narrators whose viewpoints are more than just mildly sympathetic to the plight of Husayn and his followers. They are practically identical to the early Shi'i perspectives on the battle.  However, despite the Sunni community's readiness to incorporate pro-‘Alid and pro-Husayn narrative accounts into the literary corpus, the new public commemoration rituals marking Karbala as the central symbol of Shi'i identity were not so welcomed by the dominant Sunni culture. [...] Ibn Kathir includes an entry [...] describing the Muharram procession for that year, which he describes as a "despicable innovation." It seems that the religious symbolism of Karbala began to have an effect even on the Sunnis of Baghdad, such that they began to adopt a set of religious symbols of their own, resulting in a twisted re-creation of the early civil wars. In his entry for the year 363/973 In Kathir states, “In this year on Ashura, the despicable innovation was celebrated according to the custom of the Shi‘is. A great riot broke out between the Sunnis and the Shi‘is, both parties being of little intelligence. A group of Sunnis placed a woman on a camel and called her ‘A’isha, and someone took the name Talhah, and someone took the name Zubayr, and they said "We are going out to fight the followers of ‘Ali!" Many people on both sides were killed.” This is not only a remarkable historical reference indicating the level to which the Ashura procession had developed under the Buyids but also an indication of its use as a symbol of the Shi‘is' communal identity as distinct from that of the Sunnis. Moreover, this particular reference shows how such developments made the Sunni community defensive of its own identity and also reveals an increasingly dangerous dichotomy of symbolic representation with lethal consequences.

Since the antagonistic and politically dominant Umayyads were eager to sweep the [Karbala] affair from public memory, their sentiments against the commemoration of Husayn's death seem to have prevented any possibility of public commemorations without inciting a government purge. Moreover, there appear to have been efforts on the part of the Umayyad dynasty to actually neutralize the commemoration of Ashura by the Muslim populace. Historical sources even indicate that during the reign of the Umayyad caliph ‘Abd al-Malik b. Marwan (r. 65-86/685-705), the general al-Hajjaj b. Yusuf al-Thaqafi went so far as to institute a special festive holiday on the day of ashura.* It is quite likely that al-Hajjaj's deliberate institution of a festive holiday on the exact anniversary of Husayn's gruesome killing and decapitation only a year years earlier was a deliberate attempt to counteract what had by then become an increasingly disturbing trend: annual gatherings mourning the killing of Husayn and his family at the hands of the Umayyads. The annual gatherings during Ashura appear to have kept the memory of Husayn alive not only in terms of commemorating the anniversary of his battle and subsequent death but also by perpetuating the oral transmission of accounts of the battle, the events leading up to it, and its aftermath. Considering the Umayyad's antipathy toward any remembrance of Husayn and the Umayyads' repression of ‘Alid movements, the lack of documented written accounts of the battle in this period is completely understandable. Moreover, that the few Umayyad historical sources that do exist involve only the history of the Prophet seems to indicate Umayyad attempts at self-legitimation, whereby Umayyads reinforced their on piety by stressing the life of the Prophet and simultaneously averted focus from the internecine confrontations that occurred after his death. [...] The historical sources indicate that Husayn's grave site was by the third/ninth century so popular and, apparently, the commemoration of his battle and death so moving to the masses of visitors that the Abbasid caliph al-Mutawakkil (r. 232-47/847-61) destroyed the shrine of Husayn, razed Karbala, and banned visitation of the site on pain of death. Though we have only a few textual references to this in historical sources, the lack of elaboration in Abbasid-era texts actually speaks volumes. This is particularly startling, since much of the corpus of early Islamic sources was authored or compiled in third/ninth century Baghdad. As such, the significance of this act on the part of the Abbasid caliph cannot be overlooked. On one level, it shows the extent to which ritual visitation of Husayn's shrine at Karbala had developed by that time, a possible indication that ziyarah [pilgrimage] was by then already fully developed. On another level, it seems to indicate the above-mentioned discrepancy that developed in the different points of view between the Abbasids and the ‘Alids with regard to Karbala. Although the Abbasids interpreted Husayn's battle at Karbala as an anti-Umayyad battle, the destruction of Husayn's shrine and subsequent ban on visitation indicate that the commemoration rituals had by then likely acquired rebellious antigovernment connotations that were just as threatening to the new Abbasid dynasty as they were formerly to the Umayyads. *Al-Maqrizi notes that the Ayyubids reinstituted this festive practice in a deliberate attempt to replace the Fatimid commemoration of Ashura as a day of mourning.