Ok, the piton Surehand has its name written in Terran and Undercommon in between its designs. It grants a +5 to Climb checks, and a +5 to Tumble checks used to reduce the damage from a fall.
The dagger Darkwish has several powers. It was made by being that live underground, and bearing the dagger is a mark of their favor. While underground the bearer will discover many things about the nature of earth... Yeah, so basically I'm going to keep some mystery surrounding Darkwish, sorry Kelthet, you'll have to figure it out as you go.
Toungesinger, as far as Phaern knows, allows one to understand and speak in whatever language is spoken to him, but only to him. If he puts it on, he'll hear some vague whispers every now and then, and any language he hears is automatically translated into Faen for him as long as he wears the ear cuffs. That's all he knows so far.
Sekaris-lam works as Lykis says, if you care to test it before heading underground. Vesune will actually be a little tickled that you cared to try it out.
Fault-finder also works as advertised, providing you can find any unstable rock to check it on.
The ancestor statue of Yi-Feras and her daughter Ea-Seldon, along with the golden dagger, Atlas you only know how these statues are usually honored, with the burning of insense and the recitation of prayers of praise, thanks, and pleas for guidance. Those more devout priests that use the daggers also usually press the flat of the dagger to the forehead, lips, and chest (mind, breath, and heart) before touching them to the statue. Some stranger priests would offer drops of blood from all three places or even heat the dagger, burn their palms with it, and place their burned hand on the statue to make their pleas (these priests are often renegades). But you would know that speaking to the dead can require very devout prayers, particularly if you seek a vision from an ancestor.