Thanks a lot for your answer Skaballet.
I had heard that Wharton's support is strong; for the other ones I had no idea but it seems that it will be very tough. She is a brand manager in a FMCG company btw.
From what I know of the Kellogg JV club (for partners of students), it's like skaballet said: they can give support and help with suggestions on how to find jobs, but don't really have any influence on hiring decisions or visa sponsorships. Also, Kellogg's career office does not provide support for JVs.
A brand management position is going to be particularly tricky. A lot of US consumer companies don't like hiring internationals into brand management positions because they have concerns about how well the person understands US culture and, as a result, how effective they'll be in selling to US consumers.