Can somone recite namaz or quran or do some other pious work for someone instead of paying the amount of Radd e Mazalim . The peraon does not know if he owes anyone but is doing it as safety precaution. Also if he has money but does not prefer to give that money abd instead do some pious work .

Yes it is allowed hire some for performing Marhumins qaza salat and Roza and Hajj but all these ebadat cannot be done for those who are alive. Also if you don’t want give money someone in order to avoid making him/her lazy, you can ask them to recite Quran but for your Marhumins or you help him/ as Qarzul Hasanah and tell them whenever would have money give it back to me just to make him understand that he is not free to take that money and spend it. While you have intention not take it back.