If you are travelling with family, or primarily for a family vacation rather than just photography then less lenses is better.
This depends on how patient you family is of course. Less stuff is lighter carry around too
Having said that I think that something wider than your 18-55 is essential for typical European towns and cities. My admittedly biased recommendation is the magic DA15.
Out in the countryside with landscape an UWA fits all of the view in but this perspective also diminishes the impact of distant subjects, like those spectacular mountains in the horizon etc., so it's not always the first choice for landscapes.
Your 35 /2.4 would be handy for indoors , low light and it's small and weighs practically nothing so I'd put that in.
I think the 50-135 might be less useful for just scenery but lovely for family holiday potraits and for the zoo as you said. Weathersealed for the German winter conditions.
I just had a few weeks in London, UK countyside & Paris on family vacation.
I took DA15, FA31 and 18-135 (also a Sigma 8-16 last minute inclusion but i didnt carry it around every day)
We had really, really nice weather so these were mostly outdoors, and some places we went (castles/palaces etc) didn't allow photo inside
from a couple of thousand shots
18-135 was 57%
DA15 was 27%
FA31 was 14%
8-16 was 2% I only took it out once for some night shooting in Paris.
Very often i felt that the 18-135 just was not wide enough and most of my 18-135 were taken in the 18- 85 range and a handful at 135mm
What would have been ideal would be a nice weathersealed, silent focussing, DA 16-85 lens with decent IQ. I wonder where we could find on of those.