> Stephen Foster's "O Comrades, Fill No Glass for Me" is a temperance
> song of sorts (long before the Temperance movement, however.)

The temperance movement goes back to the 1830s, though it didn't start creating its own songs until a bit later. The earliest ones I know were written by the Chartists in the 1840s; in its early days temperance was a secular movement with strong socialist links, and the church wouldn't have anything to do with it (in Scotland it depended on funding from brewers and distillers). Temperance songs didn't develop significant Christian content until the 1860s, when the church was getting on the bandwagon and trying to turn the movement to its own ends.

It would be interesting to know where Foster got the idea. I don't know anything about his politics.