For spousal sponsorships, income is not required. Having said that, there were cases with refusals. To make a strong case, you may want to give IRCC a whole picture of your financials, your earning ability and your spouse's employable skills etc. The idea is to persuade officers you have the ability to support yourself and spouse rather than sending spouse gor welfare. If you have children, request considerarion of humanitarian and. Compassionate. That helps.
Onus is always on applicants to best present their case.
In terms of a parent sponsorship, officers must refuse the application if the sponsor fails to meet LICO. It is set in stones. Officers have no discretion. Sponsors are required to meet this financial test throughout the process. If one of the bad yrs is after submitting the application, your best bet is officers don't request for updates. Given the faster processing in general, it is possible they don't ask.
Ivory