Do we know if the stat's on the Swornbreaker are always the same?
I am not sure, but I *think* the one I crafted from the pieces in the Nameless Isle was different because I was lower level. I can tell you that the one I got in the vault later in Arx was level 16 and had the same stats but much lower damage.
Do we know what the smaller eternal artifacts are used for?
Haven't been able to figure it out yet.
There are also some special tea recipes you can find near the end of the game:
Black / Green / White Tea Leaves + Teapot =
Black Tea : 75% Fire Resistance 3 turns
Green Tea: -2 AP Cost 3 turns (minimum is still 1 AP I believe, this is still so OP)
White Tea: 2 Max AP 3 turns
The Teapot is in Lady Paulina Kemm's room. You get the tea leaves from her by buying some, if you're noble (I think) you can ask for some, and if you listen to her long story she gives you a cup of each. The recipes are upstairs in Justina's room I believe.