11.33.3 Can you answer these questions?

11.33.3.1 Package fontspec Error: The font "--" cannot be found

https://tex.stackexchange.com/landing/r/digest?cta=question&id=742725

Following this answer, I managed to get specific fonts in specific sizes, but here is another problem: 
\documentclass{article} 
\usepackage{fontspec} 
\setmainfont[% 
IgnoreFontspecFile,% 
... 
[fontspec]
 

asked by Niranjan https://tex.stackexchange.com/landing/r/digest?cta=user&id=174620 Score of 3

11.33.3.2 Compress page ranges in index with hyperref package

https://tex.stackexchange.com/landing/r/digest?cta=question&id=742767

When hyperref is loaded, page ranges in the index are encapsulated with \hyperpage which takes care of linking the page ranges to the right place. 
biblatex contains the \mkcomprange macro which is ... 
[biblatex] [hyperref] [indexing] [imakeidx] [makeindex]
 

asked by David Purton https://tex.stackexchange.com/landing/r/digest?cta=user&id=87678 Score of 1

11.33.3.3 pgfplots 3d schoolbook style (grid/tick marks)

https://tex.stackexchange.com/landing/r/digest?cta=question&id=742746

I'm trying to recreate the look of a 3D coordinate system as used in German schoolbooks. 
Below, I've included a minimal working example (MWE). The code that handles the grid and tick marks is quite ... 
[pgfplots]
 

asked by Sammy https://tex.stackexchange.com/landing/r/digest?cta=user&id=395186 Score of 1