I agree about the 40-20-40 seat. It's one of the most practical features on these trucks. As for the V8 options, I think we'll have to wait for the official ordering information before we know what's actually available.
It's too early to say. The 2027 3.0L Duramax is based on the LZ0 engine with ongoing improvements, but there's no evidence yet that it has completely resolved all the issues seen in the 2019–2026 models.