1) They can stand anyhow
My answer: 10!
2) All the bridesmaid must be on the left, and all the groomsmen must be on the right
My answer: 5! x 5!
3) The bridesmaids must be kept together
My answer: 5! x 6!
4) She must start with a bridesmaid to the left and end with a groomsman to the right.
My answer:1 x 8! x 1
I feel like I'm missing something for number 4. My thinking behind it, is that there is bridesmaid on the left and a groomsman on the right, and the remaining people are organised in 8! ways.
1), 2), and 3) look OK to me.
As for 4), you can choose the bridesmaid on the far left in $5$ ways, and you can choose the groomsman on the far right in $5$ ways. The remaining $8$ people can be permuted in $8!$ ways between the bridesmaid and groomsman in the extreme positions. So I would say that $25 \cdot 8!$ is the correct answer to 4).