Ampharos wants Focus Blast > Cotton Spore.
Walrein is easily replaceable for something else, as it's Attacking stats are pretty awful. If you are intending to use it with that in mind, I'd drop Earthquake for Toxic, and Surf for Substitute, as it is a pretty bulky Pokemon. It can still be used offensively, but it's offensive Movepool is shallow. Offensively, it can run Surf / Ice Beam / Substitute / Hidden Power (if it is Electric, Fighting or Ground). Otherwise, use Toxic in the last slot.
Hope this helps.
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