Hi Klaus,
Note that \lyricsto implicitly starts \lyricmode. (Also I'd recommend writing Mond __ if the note with the syllable "Mond" has a tie.)That one is a bit tricky. It is a half and a quarter note that should sound like a dotted half note. But the "Mond" should be sung only on the half note and the quarter note should be silent. So my "Mond _" consumes the "b" after the compound note which should be the "ü". from "überm". So is it possible to have the syllable just on the first note even if they are bound together?
I'm afraid I don't quite understand. If the quartet note should be silent, I think you'd better write be a rest. But probably you just want to say that there is no new syllable on the tied note?
Anyway, it's important to have __ (two _, not just one). Then the result using Ro -- ter Mond __ ü -- berm is
which, to me, looks fine.
Best
Lukas