If you’re having trouble finding both things in the same area or just have bad luck with grenade throws, then go to the town hall.
Although it’s a pain to get back to it has a grenade on the balcony & a suicider in the courtyard below. Use the warehouse as your starting point. To reach this you have to enter the very southwest sewer entrance in Moresby. Once in the sewer run straight until you hit a wall, then go left. The rest of the sewer is pretty linear & easy to figure out.
Sewer Entrance on the Overhead Map:
Sewer Entrance Door:
Clip showing where the suicider is in city hall.
If you think of something else that would benefit this guide, please post a comment about it & I'll consider adding it to the guide.