I'm not too sure about this. However, I would say that it is Ok to say attached is the assignment. It seems wrong, but to make it seem more natural, maybe try adding extra words like requested.
Explanation:
1.Correct
2.Those shoes will go on sale next week.
3.My cat is a Siamese.
4.Correct
5.Correct
6.On Tuesday evenings,I am at my yoga class.
7.Self confident people tried almost everything.
8.Correct
9.Those three cats sit in the windows.
10.Correct
<em>hope</em><em> </em><em>it</em><em> </em><em>helps</em><em> </em><em>u</em>
While Aaron traveled to India last summer, his brother James traveled to China.