Tax question

I had opened another thread to ask a visa-office related question but thought it appropriate to ask an unrelated question in a new thread.

My wife, a Canadian citizen, is sponsoring me but her income (except CCTB) was 0 in both 2009 and 2010. She received CCTB in 2009 and hence filed for her taxes and has the NOA and should be able to get a Option C printout. However, she did not take CCTB in 2010 and hence did not file her taxes in 2010 and does not have NOA nor Option C printout.

My questions are:
1. Is CCTB considered social assistance from the govt.?
2. Is it mandatory or at least recommended for her to submit NOA/Option C printout to CIC for 2010? Or can she attach a note saying that her income was zero and hence she did not file her taxes?
3. I keep reading mixed opinions on this forum about sponsor's income being 0 when sponsoring a spouse. Some say that 0 income is not an issue at all as long as the sponsor is not taking govt. assistance and apparently some people got approved easily. Other's say that CIC will have to be thoroughly convinced that the sponsor can support the applicant and this can only be done by means of documented evidence? Which group is right?
4. How important is the applicant's income? Since I am the one who has been earning the income and providing for the family (wife and son) since we got married 3 and 1/2 years back, I have Canadian and US tax returns to show evidence of my income. But will CIC even consider such income as relevant to the case?

Please help.