Old Willow, Pantera and Kailon are in the svmap and none of them are required to open portals. Ephilos, Silvanus and Sirvana are the only ones required to kill for portals to be opened. You can double check this by looking at the "Level" for the portals on the 50.svmap
Just set it to (100,2000) since those bosses are not connected to any portals. The portals that lead to those bosses are opened by defeating different bosses which are already in the obelisk.ini