No teacher should be working unpaid during the holiday. My union has been particularly strong on this and has ensured that as many staff as possible are kept safe at home. Guidance for HTs and LAs has been crystal clear.
Any staff working over the Easter break should only be there if they have been offered overtime pay or TOIL and staffing for the holidays should only be conducted on a volunteer basis. Staff cannot be compelled into working. This would be the same for the summer holidays.
As a PP said, this is only one person's opinion and I highly doubt it would happen. Either the schools will reopen in early June or, more likely, for the new academic year in September.