Punctuation, grammar and word questions

Hi. Some problem areas (as I think they are) are highlighted/underlined with some comments/question points on the side.

1.He needs to answer pop music-related questions. -- properly hyphenated?

2.Pop art-influenced images are on the wall. -- properly hyphenated?

3.He talks on the issue of over XX years of Chinese living in XXX. -- can the underlined OK as what follows the word "of"?

4.In this exhibition, seven of his most work is on display. -- should it be "work" or "works"? If we think "work" is OK, then can we use a number like "seven" to quantify it?

5.Email Hands-on training on creating free e-mail accounts, sending, checking and replying to messages. -- I feel there should be more after "sending". As it is, it doesn't make sense. What do you think?

6.Kids in grades Kindergarden-6th are welcome to join.

7.Please bring your 3-6 year olds to our fun club.

8.This is another question:

When you have two objects, a pen and pencil, on the table. Can we say/write like these?

The pencil is right of the pen. The pencil is to the right of the pen. The pencil is on the right side of the pen. The pencil is next to the pen, to the right of the pen. The pencil is on the right of the pen.