Could someone.......help.......?

Are the bottom sentences correct?

1. Jennifer gave the flowers to John and I.

Jennifer gave the flowers to me and John.

2. Each of the classes have received the new textbooks.

Each of the classes has received the new textbooks.

3. If John or his sister show up, they will receive a warm welcome.

If John or his sister shows up, they will receive a warm welcome.

4. Everybody who signed up for the tryouts are students in Mrs. Johnson’s chorus class.

Everyone, who signed up for the tryouts are students in Mrs. Johnson’s chorus class.

5. An employee needs to verify that their password is changed each month.

An employee needs to verify that his/her password is changed each month.

6. Based on the bench press test, Sarah is stronger than me.

Based on the bench press test, Sarah is stronger than me.

7. Neither Marianne nor Cindy want to accept the new assignment.

Neither Marianne nor Cindy wants to accept the new assignment.

8. When a student comes to class, you should have completed the assigned readings.

When a student comes to class, they should have completed the assigned readings.

9. The coach, as well as the players, were apprehensive about the game.

The coaches, as well as the players, were apprehensive about the game.

10. Five hundred dollars are a lot to pay for that run-down car.

Five hundred dollars is a lot to pay for that run-down car.