7000 Dying Rats

You described them very well, but I can't see how this is avant, let alone prog-avant?
Can we keep it at Grindcore with a sense of humor?
Based on these samples I'd say here is where they belong.

^ no, what you quoted are defining elements of avant-prog. Not any avantgarde is a form of progressive rock. 

Sheavy wrote: "- Fusion of disparate musical genres" "- Extremely complex and unpredictable song arrangements" - From Avant garde definition.   The song Altar Of Goat Skulls switches from black metal to what sounds more like a Prog electronic song, the Pegasus Boyd song mjixes Jazz with grindcore.....   Ballad Of Chico (on myspace page) is some sort of almost symphonic metal intro like song etc etc.

And here was me hoping that new genre definition would make things clearer...

If you're going to start quoting it out of context, let me do the same. Here's the first sentence:

"Avant-prog is an umbrella term which refers to any progressive rock artist with a strong leaning towards avant-garde and highly experimental approaches to music."

So, before we even examine their avant-garde credentials we need to ask "is the band in question a progressive rock band?". In this case the answer is clearly no.

What I hear is Prog, hence my quoting of the definition.

Hey, this band is good!