About 10% of Canadians are below the LICO. Many of those people are probably relatively near the LICO, other's farther away. I don't know much about the depth of poverty, which is why I'm not sure how much it would cost. In the long run the cost would likely decrease as being below the LICO is self-reinforcing. (People who grow up below the LICO are likely to stay there). I'm not saying their wouldn't need to be some tax increase, it's just not clear how much you would need.

The closest estimate I have seen comes from Jim Mulvale

https://news.vice.com/story/a-radical-plan-to-end-poverty-is-gaining-momentum-in-canada

Mulvale thinks that, in the short to medium term, Canada should use a targeted basic income where only low-income folks would receive the benefit — the lower your income, the higher the benefit would be. He said that, when only low-income working people receive the guaranteed income, estimates put the cost at around $35-billion.

To me, 35 billion isn't an insurmountable number. Some trimming of fat, some minor tax increases should cover it.