it is my fault

Hi,
Would you please help me with these?

[1] Which choice is the correct and natural?
- Yesterday someone broke into our home; my family are saying [______]
1. it is my fault for not locking the window.
2. it was my fault for not locking the window.
3. it is my fault for having not locked the window.

[2] Can we omit "for" here? If so, which is common, with or w/o "for"?
- It was your fault (for) not listening to the announcement.

[3] Would you please check if these are correct?
1-1. It was your fault for not backing [them, the data] up.
1-2. It is your fault for having not backed [them, the data] up.
2. It is/was your fault for mispelling - a spell checker doesn't do everything!
3. It was your fault for not putting the lid (on it).
4. Maybe it was your fault for putting your book on a crappy table.
5. It's pretty much your fault for not being smart enough to know that.

6-1. It was your fault for acting that way - you asked for it.
6-2. It was your fault for (acting) the way you did - you asked for it.
7. I don't think it's your fault for what your kids think.

Thanks a million.
Ann

[Rusty]

[1] Which choice is the correct and natural?
- Yesterday someone broke into our home; my family are saying [______]
1. it is my fault for not locking the window. (OK).
2. it was my fault for not locking the window. (OK).
3. it is my fault for not having <strike>not</strike> locked the window.

[2] Can we omit "for" here? If so, which is common, with or w/o "for"?
- It was your fault (for) not listening to the announcement. (Include for).

[3] Would you please check if these are correct?
1-1. It was your fault for not backing [them, the data] up. (OK).
1-2. It is your fault for not having <strike>not</strike> backed [them, the data] up.
2. It is/was your fault for misspelling - a spell checker doesn't do everything!
3. It was your fault for not putting the lid (on it). (Include "on it").
4. Maybe it was your fault for putting your book on a crappy table. (OK).
5. It's pretty much your fault for not being smart enough to know that.(OK).

6-1. It was your fault for acting that way - you asked for it. (OK).
6-2. It was your fault for (acting) the way you did - you asked for it. (OK. The meaning changes when you omit "acting." I then understand it as: ...the way you did something).
7. I don't think it's your fault for what your kids think. (OK).