Deadheading does count towards productivity pay. It wasn't originally but that changed. The other duties receive no credit full stop, let alone productivity!
The above 'freebie' duties are supposed to have a phantom credit attached during roster but it's either not working as planned or, more likely, ignored to increase efficiency at our expense. I've often found my roster just below the productivity threshold but there will be SEP, sim or other non credit duties rostered. That way 100-105 hours a month can be done whilst only being payed for 92.