Translation for the yellow texts:
"Gone is the Morning Musume。 you once knew.
We’ll improve both ourselves and idol world.
It’s an evolution resulted from 16 years long process, not the change that happens abruptly.
10 girls who met by chance to become the 10 girls of destiny.
We won’t give up on becoming the cutest and the coolest.
We’ve become strong enough to carry everyone’s expectation.
The girls who admire that era, are now trying their best to surpass it.
We’ll always stand up no matter what, both in life and idol world.
To stay freshest.
To be the best.
To be the most beloved.
It’s still way too early to decide if we’re finally back to our finest time yet.
Shall we go, then?”
Sources: 1, 2
I think this whole CM is addressing some of the issues that has been going down in the fandom for awhile. For instance some older generation fans have a hard time adjusting to the change of the music direction as well as to the girls themselves. It's a pretty clever idea to acknowledge Morning Musume's past while talking about the present and thinking about the future.