1)
Why does it repeat the Kesefos? They were taught above (verse 30)!
1.
Rashi: This teaches that they were part of the Mechonah (molten together with it).
2.
Gra: These are an additional four pillars coming out of the corners of the Mechonah, for it was square at the bottom and round on top. The pillars helped to support the Kiyor. Malbim - the verse teaches that these were molten together with the Mechonah, for they never needed to be removed. The other Kesefos were made separately and connected to the Mechonah, and removed when they needed to take the Kiyor out or return it.
