The KDE neon website states that it is based on "the latest Ubuntu LTS", which is "18.04". This is NOT the latest Ubuntu LTS. When will KDE neon be moving to 20.04?

Probably at some point after 18.04.1 is released, near the end of July. This is how it went for the move from 16.04 to 18.04, which happened in September 2018.
There is no set schedule or expected date for this, afaik.

Waiting for the first point release of Ubuntu allows for any possible installer or similar bugs to be fixed etc. Neon also enables the HWE kernel/driver stack which keeps things more up to date. Currently we have the 5.3 kernel from 19.10, for example. I am also sure it gives time for the build systems to be properly set up for the new base.

claydoh - many thanks for posting, very interesting.