My findings for d3a6c2b

Pavement mode:

• pedestrian street is not visible. (Like visibility of bicycle=yes at pedestrian zones #6016 but for pavement mode)

Cycleway mode:

• three dot menu entries:
  "No explicit sign about cycling here" + "A sign allows cycling here" + "Designated for cycling here"
  ... are accessible when selecting residential road, bicycle boulevard, secondary road, motorway. Not needed because of the normal cycleway UI.
• when adding protected bicycle lanes to both sides of a pedestrian road, colored lines appear e.g. for Weserpromenade, how it should be. But, it is only shown on one side for my example way. I think it's because of an overlaying area tagged as pedestrian zone.

Cool, thanks for testing it!

I don't understand your comment about "pavement mode". Could you add a screenshot or something?

three dot menu entries: [...]

Oh! Weird, I thought I tested that. Will fix before merge.

when adding protected bicycle lanes to both sides of a pedestrian road, colored lines appear e.g. for Weserpromenade, how it should be. But, it is only shown on one side for my example way. I think it's because of an overlaying area tagged as pedestrian zone.

Yes, overlaying things will overlay, ¯_(ツ)_/¯. However, pedestrian areas shouldn't actually be highlighted at all in this overlay and thus also not appear in front of these things. I will have a look.

Pedestrian street could be made visible like foot paths:

Ah I see, well, makes sense, but I'll implement that separately.