When and where did the term come up for the first time? Did Satoshi Nakamoto comment on the naming?
I'll list the mentions I've found in reverse chronological order.
It first showed up on StackExchange on August 30, 2011.
However, I often hear the term Satoshi as if it was a monetary unit.
rebuilder discussed the divisibility of Bitcion on March 23, 2011.
I'll use the term "Satoshi", as previously coined by others, to mean the current smallest available Bitcoin unit.
On February 18, 2011, kiba said,
I can't wait to use satoshi to denote a very small fraction of bitcoin.
1 satoshi = 1 microbitcent (smallest denomination)
100 million satoshis = 1 bitcoin
Are we agreed?
I cannot find anything earlier on bitcointalk.
Did Satoshi Nakamoto comment on the naming?
I cannot find a searchable copy of his writings. If I can, I'll update this answer. However, his postings were already tapering off at February 2011, so probably not.