It is all speculation. We will find out for certain tomorrow. It doesn't appear likely the meetings will "slim down" as the first 2025 midweek meeting workbook has been released with no apparent changes. Lessons we can learn from the Bible will be the next CBS book middle of next year.
The only apparent change we can see thus far is that on the jw.org servers Sing Out Joyfully will extend the number of songs to 200 (it says songs 1 to 200), which is ironic because the whole point of the first revised songbook in 2009 was to avoid having too many songs to sing. The brown book Sing Praises to Jehovah had many songs I never got to practice or even learn.
Other than this, the rest remains to be seen.