My understanding after engaging with CRA and ESDC is that if the individuals in question meet the criteria for eligibility under the CERB, they can apply using their SIN, which does not expire for tax purposes, regardless of the status of their work permit. Depending on their situation, they might or might not be able to apply online, but they will be able to do so through the call centre.
As I mentioned in my conversations with you, we are looking at ways to ensure that all vulnerable populations are receiving access and eligibility to the programs throughout the COVID-19 pandemic.