I’ll handle this question in two parts. In the first, I’ll address what the role of religion was in how Black Americans viewed emancipation, focusing primarily on the 19th century. In the second, I’ll address Black American conceptions of typology and Lincoln.

To start, I would point out that slave culture was incredibly, incredibly diverse spatially and temporally. Slaves in one colony, territory, or state or even one geographical locale (e.g. on the coast, inland, or in swampier places) often lived wildly different lives. They would do different work, be more likely to come from a certain part of Africa, have different sex ratios, have differing relationships with the broader white culture, etc. I would also make note of the fact that the availability of sources from the period is limited. For one, most slaves were not capable of writing or lacked access to the resources just to be able to write regularly or in significant volume. Oral transmission has only very recently been acknowledged by much of Euro-American scholarship for its legitimacy for use in scholarship as well, which is its own meta-historical conversation. We do have some voice recordings taken I believe in FDR’s administration (perhaps even earlier) that cataloged more actual former slaves’ accounts, either through the person or a relative that survived them.

So, while there has been a lot of great scholarship in slavery studies from about the 90s on, it has also had to grapple with certain hurdles.

As for the question proper, I would caution anyone to remember that the very idea of “religion” is a Euro-Christian construct, and the idea of the “secular” is a decidedly Euro-American Protestant construct. Which is to say that separating out slaves’ religion as different from other tools and motivations we might classify as “secular” is untrue to how the slaves themselves would have conceived of these things. To put it another way, to say that using an amulet to protect oneself is different from wielding a weapon because one is religious and one is secular is not how they would have viewed it: both are simply ways one protects themselves.

In fact, it is precisely this kind of uncritical acceptance of Christian logics that renders certain earlier scholarship on slave studies dubious. Albert Raboteau, for example, writes his seminal Slave Religion in 1978, arguing stridently for the centrality of Christianity to slave life. But Raboteau belies his biases, to my mind, in statements like “At the same time, the symbols, myths, and values of Judeo-Christian tradition helped for the slave community’s image of itself” (213). But the idea of Judeo-Christian anything is a contrivance of the early- to mid-twentieth century. The idea that there is a static or even continuous tradition to speak of that connects Judaism and Christianity is blind to the enormous diversity not just between the two but within each one. Even more tellingly, Raboteau describes “conjure” and other traditional beliefs as “supernatural,” a word that he and others apply to things that diverge sufficiently from Christian conceptions of religion: though he describes traditional healing as a “supernatural power,” would he call a minister or priest performing last rites a “supernatural power”?

To return to the matter at hand, the place of Christianity in emancipation is thus best viewed as a utilitarian one: one aspect of a broad suite of ideas, ideologies, folkways, etc. that slaves used to make sense of the world. Christianity was, to varying degrees, deeply engrained in local cultures. It is important to note, however, that many plantations might have an itinerant minister visit once every three months, and only minister to the white residents. So the image we might have of devout Southerners neatly filing into an Anglican or Baptist or Methodist Church on Sundays is virtually exclusively a sight for cities and towns of sufficient size—by no means the norm.

But where slaves were able to practice religion, Christianity could provide an enormous benefit: the ability to meet in small groups, often without white supervision. While slaves would only very rarely be allowed to read even a Bible, Anglican ministers especially often pushed to be able to minister to slaves and/or to train one slave who showed particular promise to catechize the other slaves. In these cases, the slave may even be able to travel to nearby plantations on Sundays. In some cases, slaves from neighboring plantations might be able to meet together in a small group as well. So you may see a pattern forming here: Christianity gave slaves increased chances to share ideas with one another.

Naturally, the conversations turned to emancipation, if only when the present company was deemed trustworthy and there was sufficient guarantee of privacy from white folks. Christianity also gave slaves a group of shared idioms: stories to share, names to name, songs to sing, etc. As anyone with shared experiences would, slaves often began to express those experiences through the shared idioms Christianity provided. It also furnished a shared source of authority to appeal to, even where individuals may not have considered themselves Christians nor was the speaker making a direct claim on divine command. Written words have fascinated people from non-writing cultures in various instances: amulets might contain words written on them in a language the person didn’t even speak (because their language had no writing), and the mere fact that they were written down made them powerful.

in one example from a slave rebellion in Virginia in 1800, Gabriel’s Rebellion, a recorded conversation between the two men planning the rebellion was later remembered: “Martin said there was this expression in the Bible, delays breed danger. I told them that I had heard in the days of old, when the Israelites were in service to King Pharaoh, they were taken from him by the power of God, and were carried away by Moses.” We should be reluctant to assume this means the slaves involved were literally in belief that they were on a specifically religious quest: this is literally the only mention of the Bible in all their recorded conversations. And while they did meet under the guise of religious services and at a church, this gets back to my earlier point: Christianity was a tool along with all their other ones. Martin and his interlocutor looked at the Bible and said “this seems like a good piece of information to help our situation” in that moment, and never again used the Bible (at least in the events they later recounted). If religion were especially important, wouldn’t it pop up more?

And this is an apt segue to a point you hinted at: white abolitionism was positively suffused with typology. I speak a bit about that here. In the case before us, we might look at Angelina Grimke’s Appeal to the Christian Women of the South, which relies almost exclusively on Biblical reasoning and examples to prove the abhorrence and wrongness of slavery. Indeed, she points out that “It is contrary to the first charter of human rights given to Adam, and renewed to Noah,” this after she has just warned of what happens when this covenant is rejected: “Open the historical records of that age, was not Israel carried into captivity?” This is wholly in keeping with the literalist understandings of the Bible that are very much de rigueur for the evangelical Christianities heavily associated with abolition.

I would thus say you’re right to be suspicious of the actual relevance of typology to Black America at the time. Of course, there were plenty of slaves who were very devoutly Christian who, like their white abolitionist counterparts, were very invested in a personal experience of God. But whereas I would attribute to many white abolitionists and slaveholders/proponents a literal understanding of their place within Biblical history, I would argue that it was far more typical of Black America to derive hope, impetus, inspiration, and moral authority from Biblical stories.