It's worked for 20 years in the US live, and this is an even simpler version. The biggest problem though is the consecutive night scheduling on Seven, especially if they can only do Sun-Wed. (Do Seven have AFL on Thursdays?)
The easiest way is to have evictions at the end of the week (so Wed) but that doesn't feel right for Australia. There are currently 4 components to the show though that could be the centrepiece of each night - the shopping task, the nominations challenge, the nominations and the live eviction.