The Covid-19 lockdown does not change any law around public holidays (or any employment law)
The lockdown does not change ‘what is otherwise a working day’
If you work on a Good Friday or Easter Monday you are entitled to time and a half and an alternative holiday (unless you don’t normally work Friday/Monday)
If you don’t work on the public holidays you are entitled to a paid day off (unless you don’t normally work Friday/Monday)
If you have made alternative arrangements with your employer about your pay during the lockdown (as part of the wage subsidy for example) then these still need to be met; you can’t be paid less than what was agreed because there are public holidays.