1. That isn't relevant here. If you follow by the books, you would look at `addr:housename=` . Besides, another rule is not to artificially make composite names, ie combining different features' names. 
2. It's the best option. All this does is make managing building names more complicated. 
3. Not a data problem. Carto is a static raster map background. Any proper application should have more overlays and clickable buttons. 