With a 12pt font as the main one then footnotes are set using a 10pt font, so you are OK.

You can get the current fontsize like this:

\documentclass...
\makatletter
\newcommand{\showfontsize}{{\f@size pt}}
\makeatother
\begin{document}
Some text\footnote{Footnote with a fontsize of \showfont}
\end{document}

Do you really want zero \parindent? When a paragraph break occurs at a page break how is the reader to know that the second page starts with a new paragraph?

With a 12pt font as the main one then footnotes are set using a 10pt font, so you are OK.

You can get the current fontsize like this:

\documentclass...
\makatletter
\newcommand{\showfontsize}{{\f@size pt}}
\makeatother
\begin{document}
Some text\footnote{Footnote with a fontsize of \showfontsize}
\end{document}

Do you really want zero \parindent? When a paragraph break occurs at a page break how is the reader to know that the second page starts with a new paragraph?

With a 12pt font as the main one then footnotes are set using a 10pt font, so you are OK.

Do you really want zero \parindent? When a paragraph break occurs at a page break how is the reader to know that the second page starts with a new paragraph?

With a 12pt font as the main one then footnotes are set using a 10pt font, so you are OK.

You can get the current fontsize like this:

\documentclass...
\makatletter
\newcommand{\showfontsize}{{\f@size pt}}
\makeatother
\begin{document}
Some text\footnote{Footnote with a fontsize of \showfont}
\end{document}

Do you really want zero \parindent? When a paragraph break occurs at a page break how is the reader to know that the second page starts with a new paragraph?