Is this a replacement for Flash-Lite? Because it’s being used to serve answers for Search.

The new naming scheme seems shockingly poor though, “Pro” and “Flash” made intuitive sense to me, and Anthropic and OpenAI kept a sense of scale. Nobody is going to intuitively understand “Oh yes, Hydrogen is smaller than Carbon”, even though it is.

I don't believe so. From my use I think it is a Flash model through and through.

I have found it a good subagent workhorse for code implementation, with some higher level model doing the spec and review.

No. It has the same price with 3.8 flash (with no introduction price it seems)