Knife clone didn't allow Sol to be at two places at the same time but allow him to have a helper competent enough to last against a Lesser Demigod.
Combination of conjuring ability could give birth to a lot of possibilities, the sun ice and healing dome results in unbreakable ice which was stronger than sun ice standing alone, with the addition of dark eternal fire it created high-density solid material that won't disappear like the other conjured material.
As for the sun ice and knife aura, it allows the ice to move with the help of swift aura but there was a limitation to this ability, first, the aura needs enough time to accumulate swiftness before it could move the clone, the longer it has been active, the more fluid the movement of the clone was.
The second limitation was it need a core to move which was the knife armament, without the knife's presence, it would be a body without a brain, it was possible to function but it would not, because there was nothing controlling it.
