MultiMarkDown and biblatex citations

Question

I'm using Scrivener to produce LaTeX output with MultiMarkDown. MultiMarkDown uses natbib by default, so footnotes look like this code snips:

\footnote{~\citep[<prenote>]{<key>}}

The issue is that I need to use biblatex. I can get the footnotes and citations to parse by doing two things: (1) specifying the natbib option in the \usepackage{biblatex-chicago} command and (2) using \renewcommand{\citep}{\Cite}

The problem is that \footenote{\cite{}} doesn't work the same in biblatex as \footcite or \autocite. The first variant doesn't automatically produce proper punctuation after the citation, whereas the latter two variants do.

What I'm trying to figure out is how to replace the two nested commands

\footnote{~\citep[<prenote>]{<key>}}

into a single \autocite command that takes prenote and key as its arguments. Notice that MMD automatically inserts a ~ before the \citep command -- I imagine I'd have to remove that, as well, for this to work properly. The full .tex file:

\documentclass[12pt,letterpaper]{article}
\usepackage[left=1in, right=1in, bottom=1in, top=1in]{geometry}
\geometry{letterpaper}
\usepackage{etoolbox}
\usepackage{keyval}
\usepackage{ifthen}
\usepackage{url}
\usepackage[american]{babel}
\usepackage{csquotes}
\usepackage{multirow}
\usepackage{tabularx}
\usepackage{setspace}
\usepackage[notes,natbib,footmarkoff]{biblatex-chicago} 

% Euro-Symbol
\usepackage{textcomp}
\usepackage{appendix}

\usepackage{hyperref}

% Use utf-8 encoding for foreign characters
\usepackage[utf8]{inputenc}

% This is now the recommended way for checking for PDFLaTeX:
\usepackage{ifpdf}
\usepackage{times}

\renewcommand{\citep}{\Cite}

\ifpdf
\usepackage[pdftex]{graphicx}
\else
\usepackage{graphicx}
\fi

\addbibresource{Dissertation.bib}
\bibliocommand

\begin{document}

% TOC
\pagenumbering{roman}
\tableofcontents
\pagebreak

\pagenumbering{arabic}
\doublespacing

Trying to get this footnote to look normal.\footnote{~\citep[22]{Schelling:08}}

\pagebreak
\singlespacing
\printbibliography
\appendix
\end{document}

Please forgive me if this is an obvious question--I'm new to LaTeX, so any help would be much appreciated!