US pretty much forced into having to win against England after Iran's win. A loss of any kind would basically kill their chances to advance IMO -- England would be guaranteed to advance with a win at 6 points. Iran would be at 3 points with game against US upcoming. Wales is at 1 point with game against England upcoming. Wales will be desperate for a win against England to have any chance. but I can't really see Wales beating England. Then again, I didn't really give or see Iran a real chance at a win against Wales, so who knows. Iran would simply need a tie against the US to advance if England defeats the US.
Let's just say that England wins later by a score of 2-1:
England 6
Iran 3
US 1
Wales 1
England is guaranteed to advance to R16 (basically any kind of win against the US and they advance to R16). Iran has a GD of -2. US would have a GD of -1. Wales has a GD of -2.
If England beats Wales or ties Wales, Wales is eliminated. Wales now has to beat England to have any chance of advancing. A US loss or tie to Iran would eliminate the US. If the US beats Iran and the Wales beats England, US would have to have a better GD to advance