Background color for text, allowing footnotes and figures

Question

I am writing a book-like set of classroom notes using the memoir documentstyle. I would like to set off some pieces of text as 'digressions" by using a background color: I've tried two solutions, mimicking an answer to a previous question.
One uses the "framed" package:

\usepackage{framed}
\colorlet{shadecolor}{lightgray}
\newenvironment{digression}[1][]%
    {\colorlet{shadecolor}{lightgray}%
        \bigskip%
                \begin{shaded}%
                \begin{flushleft}%
                \textbf{\LARGE{Digression:}\\ \Large{#1}}\\%
        \medskip
    }%
    {%
    \end{flushleft}%
    \end{shaded}%
    \bigskip%
    }

The other uses the "tcolorbox" package:

\usepackage{tcolorbox}
\tcbuselibrary{breakable}
\newenvironment{digression}[1][]%
{%
    \begin{tcolorbox}[boxrule=0pt, sharp corners, parbox=true, breakable]
                \begin{flushleft}%
                \textbf{\LARGE{Digression:}\\ \Large{#1}}\\%
        \medskip
}%
{%
    \end{flushleft}%
    \end{tcolorbox}%
    \bigskip%
}

Both do the trick as far as getting background color is concerned, but there are two problems that remain for me: (1) if I use the first version, footnotes disappear; with the second, they appear within the box rather than at the bottom of the page; (2) neither one allows figures--the same error occurs in both (not in outer paragraph mode).
I guess the problem (especially (2)) is that this is creating a mini-page (or some analogue).
So my question is: is there a way to introduce a background color which doesn't have these limitations? I'm not in this instance interested in the bells and whistles which are useful for creating beamer slides; I just want to have a part of my page highlighted with a contrasting color.