For the original question, the modification required is:
\renewbibmacro*{title}{%
\ifthenelse{\iffieldundef{title}\AND\iffieldundef{subtitle}}
{}
{\printtext[title]{%
\printfield[apacase]{title}%
\setunit{\subtitlepunct}%
\printfield[apacase]{subtitle}}%
\setunit{\addspace}%
\printfield{titleaddon}%
\iffieldequalstr{entrytype}{book}%
{\setunit{\addspace}\usebibmacro{bookaddinfo}}%
{}%
\ifthenelse{%
\ifnameundef{author}\AND%
\(\ifnameundef{editor}\AND\NOT\boolean{bbx:editorinauthpos}\)\AND%
\ifnameundef{producer}\AND%
\ifnameundef{director}\AND%
\ifnameundef{writer}}
{\newunit\newblock
\usebibmacro{labelyear+extrayear}}
{}}}
\DeclareFieldFormat{origyear}{%
\mkbibparenss{\bibcpstring{origyear}~\thefield{origyear}%
\iffieldundef{origtitle}
{}%
{\addcolon\addspace\printfield{origtitle}}}%
}
\newbibmacro*{origyear}{%
\ifthenelse{
\NOT\iffieldundef{labelyear}
\AND\NOT\iffieldsequal{labelyear}{origyear}
\OR
\NOT\iffieldsequal{title}{origtitle}}
{\printfield{origyear}}
{}%
}
\DefineBibliographyStrings{german}{%
origyear = {Original erschienen}
}
This can be inserted in the preamble of your document.
For the extended version one has either to introduce new fields (this can be done,by modifying the data model, or by using the BibLaTeX facilities for related).
EDIT 1 and EDIT 2
To accommodate the case where the author of the original publication is different the first step is to modify the data model, this can be done with:
\begin{filecontents}{biblatex-dm.cfg}
\DeclareDatamodelFields[type=list, datatype=name,skipout=false]{origauthor}
\DeclareDatamodelEntryfields{origauthor}
\end{filecontents}
This generates a file called biblatex-dm.cfg in the current directory with the instruction about how to extend BibLaTeX data model.
Notice that BibLaTeX provides a titleaddon field and this could be used to the extra information for the title ("Die Liebe" in the OP).
Eventually, one could add a field titletranslation for the selfmade translation, i.e., one can include the following two lines in the datamodel file.
\DeclareDatamodelField[type=field, datatype=literal,skipout=false]{titletranslation}
\DeclareDatamodelEntryfields{titletranslation}
Another possibility is to use an "unused" field, for example, reprinttitle. In what follow I'm going to use this option.
The next step is to modify the appropriate bibmacros. In this case, title and origyear for the formatting of the title (and related information about the original publication)
\renewbibmacro*{title}{%
\ifthenelse{\iffieldundef{title}\AND\iffieldundef{subtitle}}
{}
{\printtext[title]{%
\printfield[apacase]{title}%
\setunit{\subtitlepunct}%
\printfield[apacase]{subtitle}}%
\setunit{\addspace}%
\printfield{titleaddon}%
\setunit{\addspace}%
\printfield{reprinttitle}%
\iffieldequalstr{entrytype}{book}%
{\setunit{\addspace}\usebibmacro{bookaddinfo}}%
{}%
\ifthenelse{%
\ifnameundef{author}\AND%
\(\ifnameundef{editor}\AND\NOT\boolean{bbx:editorinauthpos}\)\AND%
\ifnameundef{producer}\AND%
\ifnameundef{director}\AND%
\ifnameundef{writer}}
{\newunit\newblock
\usebibmacro{labelyear+extrayear}}
{}}}
For originyear the first thing to do is to define the format. To this we check that originauthor is defined, and we set the punctuation accordingly:
\DeclareFieldFormat{origyear}{%
\mkbibparens{\bibcpstring{origyear}~\thefield{origyear}%
\ifnameundef{origauthor}
{}
{\addspace\bibstring{as}\addspace\printnames[FirstLast]{origauthor}}%
\iffieldundef{origtitle}
{}%
{\ifnameundef{origauthor}
{\setunit{\addcolon\addspace}}
{\setunit{\addcomma\addspace}}%
\printfield{origtitle}}}%
}
Then we have to consider the cases when we have to output the information about the original publication (here the condition is that either the year, or the title, or the author(s) is different).
\renewbibmacro*{origyear}{%
\ifthenelse{
\NOT\iffieldsequal{labelyear}{origdateyear}
\OR
\NOT\iffieldsequal{title}{origtitle}
\OR
\NOT\ifnamesequal{author}{origauthor}
}
{\printfield{origyear}}
{}%
}
Caveat A problem with the above solution is that not all bib entry types include instructions to format the information about the original publication using the above method. A more robust technique would be to use the facilities provided by BibLaTeX to handle related publications.
The last step is to use the appropriate value for the localisation strings origyear and as.
\NewBibliographyString{origyear,as}
\DefineBibliographyStrings{ngerman}{%
origyear = {Original erschienen},
as = {als}
}
\DefineBibliographyStrings{american}{%
as = {as}
}
Finally, to change the rendering of names, we have to modify the formatting instructions for apaauthor
\DeclareNameFormat{FirstLast}{%
\ifthenelse{\value{listcount}=\maxprtauth\AND\value{listcount}<\value{listtotal}}
{\addcomma\addspace\ldots}
{\ifthenelse{\value{listcount}>\maxprtauth\AND\value{listcount}<\value{listtotal}}
{}
{\iffirstinits
{\usebibmacro{name:first-last}{#1}{#4}{#5}{#7}}
{\usebibmacro{name:first-last}{#1}{#3}{#5}{#7}}}}
\ifmorenames{\andothersdelim\bibstring{andothers}}{}}
Firstly create a dummy bibtex database having filename localbib.bib
\begin{filecontents}{localbib.bib}
@book{ mykey,
title = {The Title},
year = {2013},
author = {Doe, John},
address = {Antarctica}
}
\end{filecontents}
For the actual document, assuming `localbib.bib' as the database.
%Declare document class
\documentclass{article}
%Use Natbib and declare style options
\usepackage[numbers,square,sort&compress]{natbib}
%State database filename
\def\mybibtexdatabase{localbib} % <----- Change `localbib` here for your actual filename
%Import usebib package and declare the fields that can be used.
\usepackage{usebib}
\newbibfield{author}
\newbibfield{address}
\bibinput{\mybibtexdatabase}
%Now write the document
\begin{document}
%Example of usebibentry
Example of field citation is that %
\usebibentry{mykey}{author} is from \usebibentry{mykey}{address}, %
the publication was made in \usebibentry{mykey}{year}\citep{mykey}
%Existing methodology
\citeauthor{mykey} is the standard name citation.
%Bibliography
\bibliographystyle{apacite}
\bibliography{\mybibtexdatabase}
\end{document}
NOTE: In order to be able to use additional fields (ie for example doi, title, editor etc...) via the \usebibentry{KEY}{FIELD} command, a \newbibfield{FIELD} directive needs to be added to the preamble, just like it has been done ere for author and address.
Best Answer
A possible solution is to redefine the
cite:namebib macro with the option to print names withfirst-lastoption.