Apostrophy questions

I hope you can help me, because I am having trouble with my apostrophes. Here are my questions:

1. The witnesses; witnessess'; witness 's gave their names and addresses to that attorneys; attorneys';attorney's secretary.

2. "These conclucsions; conclusion's; are the presidents; president's; presidents'" said the treasurer.

3. He doesn't want to visit the corporate offices; office's; offices'.

4. A secretarys; secretarys'; secretaries's contributions sometimes exceed those of the manager.

5. After a few minute's; minutes' hesitation, he agreed that its'; its; it's not worth the rish.

6. Jay and Jaylene have four brothers. All four have a poor work ethic. Therefore, Jay and Jaylene aren't pleased with any of their brother's; brothers'; brothers work habits.

7. One of these agency's; agencies'; duties is to keep a record of all employee's; employees'; employees wages.

8. Children's; Childrens'; Childrens; Childrenses; clothes are on the fifth floor, next to the women's; woman's; womens; womens' department.

And one more question. Which one of the following sentences illustrates correct uses of apostrophes?

1. When writing out those POs, please be sure to dot your i's and cross your t's.

2. Mr. and Mrs. Winston P. Oglethorp III cordially invite you to an hors d'ouvre reception at five o clock in the evening on the tenth of June.

3. The old man recollected, "Youngster, 29; was a miserable year."

4. That hospital's RNs uniforms are dark green.

I think it is number 4 but I want to be sure.Thank you for any help you can give me on apostrophy help as you can see I am having trouble. Thanks again. Kathy