It doesn't seem like it, no. The sheer number of custom UI things (basically a well-designed custom UI for each and every question that can be answered) is probably the most challenging aspect to redo on another platform. And that's precisely the part that makes StreetComplete so good. I often edit with Vespucci as well when outside, but for the things that SC covers, I don't even bother fiddling with the tags, as long as I know the feature will generate a SC quest.
Some preparations and refactorings were already done in anticipation, but there's still a lot left to do.
Not really. I'm a very happy user of Go Map!! for iOS, which is a much more full-featured map editor but doesn't have the streamlined workflow of StreetComplete.
That’s interesting. Go Map!! is the only OSM editor for iOS I know about, but even moving an existing street a few yards left or right is an almost impossible chore in it…
When it comes to that sort of fine tuning, there's no substitute for JOSM, which is the all-powerful java-based desktop editor with a hundred plugins and a somewhat inscrutable UI. But it's great because it can load several sources of aerial imagery at the same time, and quickly cycle between them or set transparency levels. This gives good perspective when it comes to precise alignment of map features to imagery, and to each other.