Those pants look great, as does the shirt. I love the bright trench. The feet have to be all about comfort if you are to enjoy your days. I am traveling to 2 different climates (Europe) in late April myself, and I am planning to keep a close eye on the weather in the cities of interest.
I will be making some clothing decisions closer to the time, once I see what has been going on and is predicted. I think it will be all about layers and being prepared for occasional rain. I also plan to bring some items (scarves, pop of color in a small bag to take to dinner) that suggest spring, even though for pragmatic reasons my wardrobe will be mostly gray and black, with cream and ink accents.
Boots make sense if it is chilly and wet, but as others have noted they could be too warm and hard to pack (I wouldn't want to wear heavy boots on a plane myself, but booties wouldn't mind booties). If your comfy sneakers feel too "eye catching", try them with bootleg pants or wider straight legs sometimes. I really wouldn't sweat it for sight-seeing, as people do wear what works for them and they are not the solid white ones that scream "gym shoes" in major Euro cities. I am a big shoe insert fan. I suggest you try your inserts in all the shoes you are bringing now, to see what works best in each shoe. Spend as much time wearing each pair as possible. Then you will know where potential problem spots are and can put blister band-aids on or add moleskin to the offending part of the shoe. I have been blindsided by shoes that were comfortable enough at home, but not up to my usual 10 miles a day on cobblestones. I also take lambswool that is a miracle worker to reduce friction points in shoes, especially around toes.
Have a great trip. Thanks for sharing your ideas.