The band's problem is that the songs were commercially usable and the band has only now changed their terms of use. As a result, they first have to give DPC the chance to remove the songs so that he no longer uses them commercially, because otherwise any court would rule against the band.
The band probably hopes that DPC will continue to use the songs and pay for them. If DPC acquires the licenses now, perhaps the band could sue to have DPC demand the License payments for 4 years.
DPC, I think I read, has no problem paying royalties and can include them in its fixed monthly costs. But if the band demands License for several songs and for the last 4 years, I personally would give them the finger, no matter how much money I had.
other than that they are all your assumptions again of what they would have asked DPC for (complete with evil plan as if DPC was the last of the dummies), but mostly it is not true
but why do you think DPC wrote to them 4 years ago? out of courtesy between artists?
DPC was aware that they might not be favorable, and sought reassurance, then having received no response proceeded anyway
the conditions haven't changed (DPC doesn't say, where did you find that out?), only now the authors have responded to him and told him that they don't agree with his use of it
that a song is free means that you don't pay for it not that anyone can use it, the authors always have the final say.
then it's believable that by paying they would change their minds, money suits everyone, but it's just castles of cards, in my opinion there's no basis at all, no AVN pays, assuming DPC paid it would be pocket change that wouldn't make a difference either way
let's say even 5% of what he has earned so far (which is a huge unlikely share) we would be talking about 15,000€, you don't even pay the lawyer
When I downloaded their songs from Soundcloud, they were uploaded with the CC BY-SA 3.0 license, making them free to use commercially, but this usage wasn't what they intended.
I reached out to them four years ago about using their songs, and I got my reply this week asking me not to use their music and to remove anything I had added since.