How do I get headers and footers to extend into the margin (using the Memoir class)?

Question

Similar to what was asked in this question I’m writing a document that uses a small text block, with the margin holding some notes. I did not explicitly changed the \textwidth directly, only the margins and the marginparwidth through the geometry package. Because of the narrow text block, the headers narrow in the same proportion.

So, how do I get the header to extend into the margins \marginparsep + \marginparwidth? Also... same problem with the page numbers on every chapter's first page, they are not centered and I'd like them to be.

I’m using the Memoir class.

I've been using LaTeX through Overleaf for about 6 months now, so I'm still new. Sorry if this is a silly question.

Here's an example of what I'm doing:

\documentclass[letterpaper, 12pt]{memoir}
\usepackage[utf8]{inputenc}
\usepackage[spanish, mexico]{babel}
\usepackage{multicol}
\usepackage{marginnote}
\usepackage{lettrine}
\usepackage{enumitem}
\usepackage{blindtext}
\usepackage[
    letterpaper,
    marginparwidth=1.5in,
    right=2in,
    left=1in,
    top=1in,
    bottom=1in
]{geometry}
\usepackage{titlesec}
\renewcommand{\thechapter}{\Roman{chapter}}
\renewcommand{\thesection}{\arabic{section}}
\titleformat{\section}
{\normalfont\Large\bfseries}{Artículo~\thesection}{1em}{}
\counterwithout{footnote}{chapter}
\counterwithout{section}{chapter}
\usepackage{GoudyIn}
\renewcommand{\LettrineFontHook}{\GoudyInfamily{}}
{\LettrineTextFont{\itshape}
\setcounter{DefaultLines}{5}
\setlength{\DefaultNindent}{0pt}
\setlength{\DefaultFindent}{1pt}}
\newlist{apartados}{enumerate}{3}
    \setlist[apartados, 1]
    {label=\textbf{\Alph{apartadosi}.}
    }
    \setlist[apartados, 2]
    {label=\textbf{\Roman{apartadosii}.}
    }
\newlist{fracciones}{enumerate}{3}
    \setlist[fracciones, 1]
    {label=\textbf{\Roman{apartadosi}.}
    }
\title{TITLE}
\author{Me}
\date{September 2022}
\begin{document}
\frontmatter
\maketitle
\mainmatter
\part*{PART ONE}
\chapter[A not so long Chapter Title]{A very very very very long Chapter Title
}
\section{}
\marginnote{
    \emph{\footnotesize In this page you can see how the page number at the bottom is not centered}
    }
\noindent\blindtext \footnote{
    \blindtext
    }
\blindtext
\marginnote{
    \emph{\footnotesize In this page you can see how the header (and the page number specifically) is not the full width, including the margin width}
    }
\blindtext
\end{document}