Font switching for defined parts of document

I am lost in a maze of little twisty Fonts, all different.

I need to use a different face (font family) for small portions of my novel, possibly retaining possibility to use bold/italic modifiers.

I need a face with a readable cursive look. I tried using ITC Zapf Chancery (\fontfamily{pzc}) which is perfect for my style, but it doesn't seem to support neither bold nor italic nor small-caps for emphasis.

I tried to add a different font (it seems I have a lot of them installed in my Debian Sid box), but I fail to understand how to use them; I tried to follow this answer, but it bombs on me with "Package fontspec Error: The font "Calibri" cannot be found." (which might be right since I do not have a font named "Calibri", but I have fonts with names "URW Chancery L", "Free Chancery" and "Z003", and they give the same error).

Beside I'm not really sure I can go that way 'cause I will need to convert to ebook (probably using tex4ebook) and I'm unsure if this is compatible with lulatex/tetex (needed by \fontspec).

I can see a lot of fonts on my box (I'm using font-manager for display them), but I'm unsure how they map to LaTeX names (if they do).

Using something like \newfontfamily\theokritosfont{GFS Theokritos} usually works, but not always (what am I missing?)

What should I use if I need to use plain pdflatex or htlatex?

How can I map between \newfontfamily\myfont{Font Name} and \fontfamily{code}?

Other problem is semi-cursive fonts (e.g.: "Tex Gyre Chorus") never support italic/bold (I can understand italics, as such fonts are already slanted and standout could be done "rectifying " them, but why not allow bold?)

I understand the above is a lot of questions, while SE usually likes a single, answerable, question, but I am trying to explain I have really tried to understand the matter; base question is:

Can someone advise a Chancery-looking font, usable in LaTeX, having at least bold (better if some other kind of emphasis is also available) and give me instruction on how to use it in prectice?

There are a number of different questions there.

The font Calibri in that answer was just an example. It’s a proprietary font owned by Microsoft. Simply substitute fonts that you do have. I would definitely avoid Calibri anyway, since it’s the default font in some versions of Microsoft Word. A good substitute that doesn’t cost anything is Carlito from Google. (And, readers, let this be a lesson to you to use standard fonts and packages in your examples!)

I’d also advise you to consider very carefully whether you really want to use a bold ornate script font in your document too, unless you’re parodying over-the-top font design.

Finally, my advice about PDFLaTeX compatibility is: don’t even try. If you can, just use LuaLaTeX.

What fonts can you use? You can go to a site such as Font Squirrel and browse their selection, but there are a lot more free fonts out there. You can also look through the Debian package repository to see what fonts are downloadable. If a package is available through your distribution, you should get it from there. Otherwise, download the otf, ttf or ttc files.

For this example, I picked a clone of Palatino as the main font and downloaded Tangerine to a subdirectory of my project directory named fonts. You can also download any otf, ttf or ttc file to your ~/.fonts directory to install it for yourself, or a subdirectory of /usr/local/share/fonts to install it for everyone on your system.

\documentclass{book}
\usepackage{fontspec}

% Solely to produce a MWE on TeX.SX that fits in the allowed width:
\usepackage[paperwidth=10cm]{geometry}

\defaultfontfeatures{Scale = MatchLowercase}
\setmainfont{TeX Gyre Pagella}[Scale = 1.0, Numbers = OldStyle]
\newfontfamily\scriptfamily{Tangerine}[
Path = ./fonts/ ,
UprightFont = *_Regular ,
BoldFont = *_Bold ,
Extension = .ttf ]
\newfontfamily\calfamily{TeX Gyre Chorus}

\DeclareTextFontCommand\textscript{\scriptfamily}
\DeclareTextFontCommand\textcal{\calfamily}

\begin{document}
This text is in Palatino (or rather, its clone).
{\calfamily This is in Zapf Chancery (or rather, its clone).}
\textscript{And this is in Tangerine \textbf{Bold}.}
\end{document}


There, I used TeX Gyre Chorus (a clone of Zapf Chancery) as a script font and TeX Gyre Pagella (a clone of Palatino) as the main text font. Both of these designs were originally by Hermann Zapf, and in my opinion go well together. A sans-serif font by Zapf that also matches would be Zapf’s Optima, and in my opinion, if you need a monospace font, Inconsolata is a good choice with a humanist look. I also included Tangerine as an example of how to download and use a custom script font that comes in bold weight.

Although I kept this example standard and minimal, you might want to add the line \usepackage{microtype} to turn on font expansion and protrusion. That drastically reduces the amount of hyphenation and extra spacing, and therefore makes most documents look much better on screens.

The title of this question is not very relevant to the multiple questions you are asking.

You're completely on your own when it comes to ebooks. I doubt any converter will pay attention to anything that fontspec does by way of fonts.

When it comes to loading fonts I recommend doing it by filename to avoid all the font name lookup weirdness.

To map between \newfontfamily and \fontfamily (despite their names they operate at very different levels) you need to use the NFSSFamily option; the example given in the documentation is:

\newfontfamily\verbatimfont[NFSSFamily=myverbatimfont]{Inconsolata.otf}
...
\fontfamily{myverbatimfont}\selectfont


But where possible it's better to use the \verbatimfont switch that fontspec defines for you as that includes some additional detail like font encoding switching if necessary.