Is it permissible to make dua of forgiveness for a faasiq, faajir who was a criminal?

Answer

In fact, it is Waajib on the community to make Dua for all Muslims who die, hence Janaazah Salaat which is Dua of Maghfirat is perfomed compulsorily for every Muslim regardless of how sinful he/she may be. You may therefore make dua for the faasiq/ faajir.