Anybody remember what the "pots" mean? Is it draw four from a pot to make a group?
One team per pot makes a group. Though, outside of Europe (max 2), no other confederation can have more than 1 per group. So, if USA gets drawn from Pot 2 and Canada is drawn from Pot 4 for the same group, Canada can't get picked and they re-draw from Pot 4.
Pot 1 = Host + top 7 ranked countries
Pot 2 = 8-15th ranked countries
Pot 3 = 17-24th ranked countries
Pot 4 = bottom ranked teams + all inter-continental qualifiers (so I think Wales/Scotland/Ukraine would have all ended up in Pot 4 regardless if they advance).