Hi Scott,
The St is just the first letters in the name Stina, if you look at the record again you can see the minister just ran out of space and added the last three letters below the ST.
She was born in Pehrstorp and the family can be found at GID: 98.7.36000, page 63.
I can't help you with your last question, I don't remember having seen anything like that before, maybe someone else can help you out with that.
Have a nice day!
Don