A few questions

Hello,

I have a few questions. Thank you for your help.

Should I use a preposition in this sentence:

(I am describing the life of a famous actor)

1. His great roles were well-known and admired by audience.

(I mean general audience, TV viewers, etc.)

2. A stuntman 'doubles an actor' or 'doubles for' an actor?

3. Englishmen hang Christmas stockings above the fireplace.

I think we dont say 'The Englishmen'. We can say 'The English', though.

4. I am looking forward to hearing from you about this event.

Is this sentence ok?

When I want to invite sb for sth, should I say:

5. I invite/I am inviting you to visit me...

6. If you like such a camp, please join me on Wednesday.

(I mean the type of camp I have described before)

I am describing the life of a student (book plot). I have already spoken about the school. Should I use 'the' in front of the word 'teachers'?

7. Each lesson is very stressful because the teachers are strict.

(I mean the teachers in that school, should I use 'the' even though I haven't spoken about these teachers before?)

8. A/the lack of contact with families has a bad influence on the students' health.

9. The form of diary (no preposition before 'diary'?) makes a reader deeply absorbed in the plot.

Thank you in advance for your help.

Shadok.