Is there any clues in the film that would support this theory? For example; there are various things in
Fight Club
that are not apparent when watches the film for the first time, but become so when one knows the ending. [SPOILERS WARNING]
When "Jack" calls Tyler on a payphone after his apartment is destroyed, Tyler "star-69's" him, despite a small sign on the phone saying "No Incoming Calls
When Tyler is being beaten by the owners of the bar "Jack" flinches in time with the punches
After the Tyler crashes the car he pulls "Jack" out of the
drivers
side
"Jack" is seen carrying a camera and the folders "Angel Face" later stops him from looking at.
I'm going to have to watch F again to see if I can see anything like this.

If the characters really interacted as they did (and there is nothing to indicate that it's a hallucination of Mr. Anderson's), there is nothing to suggest that Mr. Anderson himself was murdering anyone.
I watched it twice and it's clear to me that though there is probably a unique relation between the hoodies and Mr. Anderson (because they never kill Mr. Anderson even when they had several good chances), Mr. Anderson himself is not the one killing.

Wow.. so basically you're saying The Dad stabbed his own daughter? Don't you think his daughter would have freak the sh*t out after? It makes no sense. He left with her to go to a hospital.
If you were right, she would have died by his hand and then get caught by his ex wife. That would make sense.

Perhaps he was semi-drunk and wanted an even revenge against the school that treated him unfair?

It's all left open ended and that's the way it turned out, either by bad writing or poor budget. The title F hints at lowest school graded hoodies. The memo the father circulated suggests that there are violent hooligans in the area and his school could be targeted next. The mother left alone in the school suggests she will be killed next. The hoodies scrurry around like elusive phantoms they appear to have no faces suggests that they have no independent existence beyond the father's alcoholic deluded mind.
It is just a mixed up mess full of contradictions, make of it what you will.

i have to agree, the faceless hoodies are roberts demonsas he engages a bloody rampage to get his daughter. no other explanation for the hoodies makes any sense.