The errorProvider only has one icon which is displayed against all controls which have an error text set so you couldnt show a tick for some controls and a cross for others withthe same errorProvider. One option would be to have two errorProviders. Use one to show errors and the other to show correct values. Something like:
In the designer you can change the Icon property. Create/download a suitable tick icon and set assign it to your Valid error provider. I'd also recommend setting the BlinkStyle property to NeverBlink since it will look unsightly and possibly confusing if all your ticks are flashing when input is valid.