Which leads me to wonder whether the tent-revival Universalist side of our house celebrated Ash Wednesday, and if so, what they said.
I looked in a couple of old Unitarian service books and couldn't find anything. My guess would be that since the Unitarians were an offshoot of the Puritans they had long ago purged all that papist sacramental stuff (except baptism and communion), and saw no reason to revive Ash Wednesday just because their constipated Congregational brethren had stopped talking to them.
"Tent revival" indeed. For what its worth, Universalists almost uniformly condemned revivals. They preferred days-long drag-down debates for their mass religious
Ya' have to recall that in most places Episcopalians (and other Protestants) were much "lower church" before the chain of liturgical revival movements -- Oxford Movement, "the Mercersburg theology" and the post-WWII ecumenical convergences, for example -- and so there would have been places where some Universalists wouldn't have been liturgically that far from Episcopalians. Most Protestants are more catholic (if not Roman) now; the widespread use of the Revised Common Lectionary is a good example.
In the most-likely age of liturgical cross-fertilization, the American Episcopalians would have had access particular collects (pulled out as a distinct penetential office in 1892) but not the "Commination" of the English 1662 prayer book. Ash Wednesday may have had no ashes (I'm not expert in the ways of nineteenth century Episcopalian practice) and I suspect if a service was held, it was as Morning Prayer.
Looking to Universalist prayerbooks of the first seven decades of the nineteenth century, well, I haven't looked at them all but I can't find anything that suggests an observation of Ash Wednesday. Transfiguration the Sunday before, and Good Friday weeks after, but not Ash Wednesday. Sorry.
It is worth a moment to consider the terms "low church" and "high church" -- each tends to be reduced to liturgical sensibility -- because it reflect what one thinks the church is capable of being.
Considered as a spectrum, the low option is prone to consider the action of the individual, moral improvability, the human origins of the church, and the parochial. The high option is prone to consider corporate humanity, holiness, the divine origins of the church, and the universal. Both can be beautiful and true -- and abused. Drawn broadly, low worship is "preacherly" and high worship is "sacramental." Both Unitarianism and Universalism skew "low" but there have been "hightening" (towards center) movements from time to time. Which is good: at its best, liberal churches (Christian or not) are broad: negotiating between the two extremes, thus being 'catholic'.
Oddly enough, one of the movements that gives me the biggest rash -- Ken Patten and his awful Charles Street Meetinghouse -- is an example of a liturgical, catholicisizing movement: one of my beefs with him is that he sets the ceiling so low, putting it in the realm of human phenomenon, aesthetics, and his own conception of what the truth core of religion is. So holiness is beauty and beauty is holiness. Blech!
Better choices can be "low Prayer Book" (as King's Chapel has; also the Universalist prayerbook tradition) or the "pulpit with a global consciousness" (can't think of a better way to put that) of John Haynes Holmes at alia. But that's a discussion for another era. Just let me lament the sectarian state Unitarian Universalism has crawled into, as Lent begins.