Custom author-year bibliography style

Question

I've been trying to create my own bibilography-style for some time now. In principle I managed it with a custom .bst-file, but it feels like a pain in the *** if you want to make a change or add new entry-types for example. For this reason I wanted to switch to Biblatex. The style that comes closest to the one I'd like to have is authoryear-comp. But there are some things I'd like to have different.

1. I would like to have the date at the end of a bibliography entry.
2. If there are multiple authors, the authors should still be listed with surname, first name and always be separated by a semicolon.

The bibilography in the example should look like this:

Boltzmann, Ludwig; Schrödinger, Erwin und Heisenberg, Werner: "This is a long title of article B". In: Some Science Journal. 1970

Einstein, Albert: "This is a long title of pdhThesis A". Diss. Example School, p.42-125. 1950

Here is my current code. For compatibility with my old natbib \citep{}-citations I use the natbib-key of biblatex.

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[ngerman]{babel}
\usepackage{lmodern}
\usepackage{filecontents}


\begin{filecontents*}{\jobname.bib}
@article{articleA,
title={This is a long title of article A},
author={Albert Einstein},
journal={Some scienece journal},
volume={1},
number={4},
pages={42--125},
year=1950,
publisher={Hellsevier}
}

@article{articleB,
title={This is a long title of article B},
author={Ludwig Boltzmann and Erwin Schrödinger and Werner Heisenberg},
journal={Another science journal},
volume={42},
number={1},
pages={43--49},
year=1970,
publisher={Hellsevier}
}
\end{filecontents*}

\usepackage[
    backend = biber,
    style = authoryear-comp,
    maxcitenames = 3,
    maxbibnames = 5,
    sorting = nyt,
    natbib
]{biblatex}

\selectlanguage{ngerman}
\addbibresource{\jobname.bib}

\begin{document}
This is a test for citation \citep{articleA}. And here is another test \citep{articleB}.
\printbibliography
\end{document}

Which produes

Answer 1

You could achieve these results with very little fiddling, using biblatex's customization interface.

As to your requirement of having the date to the end of the entry in the bibliography, you could combine a different bibstyle to your chosen citation style in biblatex's options. bibstyle=authortitle is not incompatible with authoryear (and variants) citation style. But notice that the differences between the two bibstyles are meant to make it easier to find an entry in the bibliography when cited with authoryear (the year gets close to the author, towards the beginning of the entry).

In case you do choose to use bibstyle=authortitle, you should also set the date to include the dateextra part (as well remembered by @moewe, in the comments), with:

\renewbibmacro*{date}{\printdateextra}

For the desired changes in name lists, you can use:

\DeclareNameAlias{sortname}{family-given}
\DeclareDelimFormat{multinamedelim}{\addsemicolon\space}

In full:

\documentclass{article}
\usepackage[utf8]{inputenc}
\usepackage[T1]{fontenc}
\usepackage[ngerman]{babel}
\usepackage{lmodern}
\usepackage{filecontents}


\begin{filecontents*}{\jobname.bib}
@article{articleA,
title={This is a long title of article A},
author={Albert Einstein},
journal={Some scienece journal},
volume={1},
number={4},
pages={42--125},
year=1950,
publisher={Hellsevier}
}

@article{articleB,
title={This is a long title of article B},
author={Ludwig Boltzmann and Erwin Schrödinger and Werner Heisenberg},
journal={Another science journal},
volume={42},
number={1},
pages={43--49},
year=1970,
publisher={Hellsevier}
}
\end{filecontents*}

\usepackage[
    backend = biber,
    citestyle = authoryear-comp,
    bibstyle = authortitle,
    maxcitenames = 3,
    maxbibnames = 5,
    sorting = nyt,
    natbib
]{biblatex}

\renewbibmacro*{date}{\printdateextra}
\DeclareNameAlias{sortname}{family-given}
\DeclareDelimFormat{multinamedelim}{\addsemicolon\space}

\addbibresource{\jobname.bib}

\begin{document}
This is a test for citation \citep{articleA}. And here is another test \citep{articleB}.
\printbibliography
\end{document}