Rob, your first example looks a bit tight, that’s why they put the pizz. of that octave, where there was space.
In the second example the engraver was probably a bit careless, when he put the fortes down - or he copied the exact positions of the original.
In your Beethoven example the symbols don’t look like x - more like some playing instruction (could be accents with strong individual vibrato). Because it is ambiguous the editor probably copied from the autograph as close as possible and left the interpretation of those signs to the interpreter. I actually prefer it that way, if I was the musician to play the piece.
I am not a cellist, but it would be interesting to know, from which piece this example derives.