~snip~
Argentina still has to qualify despite being the defending champions? Anyway from your list, only Brazil and Argentina looks certain to me. Competition is extremely strong in CONMEBOL qualifiers. Upsets can always happen and last time it was Uruguay and Ecuador who managed to qualify apart from the two top teams. Colombia lost out and later tried their best to get Ecuador disqualified. Chile and Paraguay lost out as well, and they were also not too happy about it. Peru had a golden chance of qualifying, but they lost to Australia in the playoffs.
Yeah, since a long time ago the champion of the world cup has to go back to the qualifier stage. Only the host gets automatic qualification.
The winner of France 1998, which was France, was actually the last team to qualify automatically as the champion. So, in Korea-Japan 2002 we saw this happening for the last time, more than 20 years ago.