If you looked on ScotlandsPeople and did not see them, I wonder if it is because you looked at the Church of Scotland parish registers instead of the Free Church ones?
When you click on the index for "Church registers", what comes up automatically are the Church of Scotland ones. On the index page you will also find a button for "Roman Catholic Church" and one for other "Other churches". To find Free Church records, click on "Other churches".
The information in church registers is very variable. There won't be the amount of detail you get in statutory registers from 1855. Re the two entries for the marriage, the minimum that is recorded are the names of the couple and the date they announced their intention to marry. If you are lucky, there might be more, but you won't know until you look at the originals. The reason for the two records is that when the bride and groom came from different parishes, the banns were read in both places and they had to let the session clerk in both know. You should always look at both entries as one can give details not contained in the other.
