POI Icons are not shown in "Basic"-Map Copy

[Christian]

Hello,

I'm a newbie and want to extend the "Basic"-Map with the POI-Symbols from the "Streets"-Map. So tried the following:

1. Make a copy the Streets-Map und export the Style.
2. Copy the POI-Layers (poi_z16, poi_z15, poi_z14, poi_transit) in the style.json
3. Export the Style from "Basic"-Map, paste the POI-Layers from the "Streets"-Map and the result is the attached file style.json
4. When I import the style, the icons aren't shown. Only the alternative text can be found:
   

   

5. But I'd also like to see the icons like in the streets map:

   

I can't figure out, why the Icons aren't shown. Another problem seems to be, that the Z-Index seems to be wrong - the text is  sometimes behind the streets and ways.

Any help is much appreciated

Christian