They were buried in Sts Peter and Paul so I would look there for the marriage. The FHL does have many records for this church. Here is one that would be worth ordering to look for the marriage of Henry Kaufmann and Anna Morrison.

Marriages (with indexes at end) ... 1854-1897 FHL US/CAN Film 1871463
I don't know when they moved to St Louis, as she was born in Illinois from her death cert, but you can also look at other films for the baptism of children.
If you are in St Louis, the county library should have these, if you are anywhere else a local Family History Library can order the film for you. I'd scan all indexes for the name and also your other mystery names too. I have found many great things once I can place a family in a church!