it's a bitcoin hardfork, we only changed the PoW algorithm
You'll need to change the difficulty as well.
And possibly the difficulty adjustment, since rapid hashpower fluctuations are to be expected.
You are correct, and we have.
The mining difficulty will be reset when the PoW changes, and emergency retarget has been also been implemented
that's what is written in the OP as well.
i was answering a comment about block time and rewards and didn't realize i was making too general of a statement.
The core principle is to only change what needs to be changed