Yes, you are still entitled to OPFP if unemployed. You can earn up to 425 Euro per week gross and still retain OPFP, but if you are not working, then you will get the full rate of the payment.
Obviously, when you finish the CE Scheme, you'll no longer get paid for that. While on the CE Scheme your OPFP will have been reduced because of the additional income, but when you finish the scheme your OPFP will revert to the normal rate for your family size (188+29.80 for each child)