This is supposed to coop mainly in Sens Fortress and Anor Londo and coop ranges from 35-65. May be able to coop in some other zones too.
Ring of Fog not only makes you look like a ghost but also is very powerful against PvE enemies for stealth.
Secondary ring you can put whatever you want, well both rings you can but it's supposed to be a ghost.
Soothing sunlight will heal everyone for 1200+ 3 times so pretty much full health if not full health. Instead of force you can run WotG. TWOP is there for invaders even though it's not very good unless you sneak it in without them seeing. You can also swap TWOP for Bountiful Sunlight but it only has one use and heals 600. Finally you can also go ng+ and run two Soothing Sunlights for 6 casts.