Setting up basic elsarticle document class with oscola

Question

I am trying to create a draft using LaTex which requires elsarticle.cls wa OSCOLA reference style. The instruction given by the journal is as follows:

Footnotes and References Footnotes should be used appropriately. Number them consecutively throughout the article, using superscript Arabic numbers. An authoritative and comprehensive guide to referencing is provided in the Oxford Standard for Citation of Legal Authorities ('OSCOLA') published by the Faculty of Law, University of Oxford. The Harvard Citation system may also be used. You should use Ibid. and Op.cit. where appropriate. If a reference has more than 6 authors, list the first 6 authors followed by 'et al.' If there are 6 authors or fewer, all author names should be listed.

My MVP looks as follows:

\documentclass[review]{elsarticle}

\usepackage{lineno,hyperref}
\modulolinenumbers[5]

\usepackage[backend=bibtex,style=oscola]{biblatex}
\bibliography{mybibfile.bib} 

\journal{Journal of \LaTeX\ Templates}

%%%%%%%%%%%%%%%%%%%%%%%
%% Elsevier bibliography styles
%%%%%%%%%%%%%%%%%%%%%%%
%% To change the style, put a % in front of the second line of the current style and
%% remove the % from the second line of the style you would like to use.
%%%%%%%%%%%%%%%%%%%%%%%

%% Numbered
%\bibliographystyle{model1-num-names}
%% Numbered without titles
%\bibliographystyle{model1a-num-names}
%% Harvard
%\bibliographystyle{model2-names.bst}\biboptions{authoryear}
%% Vancouver numbered
%\usepackage{numcompress}\bibliographystyle{model3-num-names}
%% Vancouver name/year
%\usepackage{numcompress}\bibliographystyle{model4-names}\biboptions{authoryear}
%% APA style
%\bibliographystyle{model5-names}\biboptions{authoryear}
%% AMA style
%\usepackage{numcompress}\bibliographystyle{model6-num-names}
%% `Elsevier LaTeX' style
%\bibliographystyle{elsarticle-num}
%%%%%%%%%%%%%%%%%%%%%%%

\begin{document}

\begin{frontmatter}

\title{Elsevier \LaTeX\ template\tnoteref{mytitlenote}}
\tnotetext[mytitlenote]{Fully documented templates are available in the elsarticle package on \href{http://www.ctan.org/tex-archive/macros/latex/contrib/elsarticle}{CTAN}.}

%% Group authors per affiliation:
\author{Elsevier\fnref{myfootnote}}
\address{Radarweg 29, Amsterdam}
\fntext[myfootnote]{Since 1880.}

%% or include affiliations in footnotes:
\author[mymainaddress,mysecondaryaddress]{Elsevier Inc}
\ead[url]{www.elsevier.com}

\author[mysecondaryaddress]{Global Customer Service\corref{mycorrespondingauthor}}
\cortext[mycorrespondingauthor]{Corresponding author}
\ead{support@elsevier.com}

\address[mymainaddress]{1600 John F Kennedy Boulevard, Philadelphia}
\address[mysecondaryaddress]{360 Park Avenue South, New York}

\begin{abstract}
This template helps you to create a properly formatted \LaTeX\ manuscript.
\end{abstract}

\begin{keyword}
\texttt{elsarticle.cls}\sep \LaTeX\sep Elsevier \sep template
\MSC[2010] 00-01\sep  99-00
\end{keyword}

\end{frontmatter}

\linenumbers

\section{The Elsevier article class}

\paragraph{Installation} If the document class \emph{elsarticle} is not available on your computer, you can download and install the system package \emph{texlive-publishers} (Linux) or install the \LaTeX\ package \emph{elsarticle} using the package manager of your \TeX\ installation, which is typically \TeX\ Live or Mik\TeX.

\section{Bibliography styles}

There are various bibliography styles available. You can select the style of your choice in the preamble of this document. These styles are Elsevier styles based on standard styles like Harvard and Vancouver. Please use Bib\TeX\ to generate your bibliography and include DOIs whenever available.

Here are two sample references: \cite{Feynman1963118,Dirac1953888}.

\section*{References}

\printbibliography

\end{document}

When I compile, I get the following error messages:

! LaTeX Error: Command \bibhang already defined.
               Or name \end... illegal, see p.192 of the manual.

! LaTeX Error: Command \c@author already defined.
               Or name \end... illegal, see p.192 of the manual.

! LaTeX Error: Command \citename already defined.
               Or name \end... illegal, see p.192 of the manual. 

Package biblatex Warning: Using fall-back BibTeX(8) backend:
(biblatex)                functionality may be reduced/unavailable.

! LaTeX Error: Command \bibfont already defined.
               Or name \end... illegal, see p.192 of the manual.

Package biblatex Warning: Redefining '\citeauthor'.

Package biblatex Warning: Redefining '\citeyear'.   

! LaTeX Error: Command \Citeauthor already defined.
               Or name \end... illegal, see p.192 of the manual.

! Package biblatex Error: Biber backend is required by style.

! Package biblatex Error: Incompatible package 'natbib'.

The 'natbib' package and biblatex are incompatible.

Since I am new to OSCOLA or these kind of errors in general, my questions are as follows:

1. what am I missing? how to avoid these errors?
2. "You should use Ibid. and Op.cit." says the instructions from the journal. I believe that can also be set in \usepackage[backend=bibtex,style=oscola]{biblatex}? If not, how?

I am on Ubuntu 18.04, and using tex-maker.