Help with making a package

Question

I'm trying to design a package so that I can 'theme' a document quickly. I've done this, but as a sort of academic exercise I'm trying to design an option compact that adjusts margins, title, and layout to optimize the document for use of multicols.

The issue here is I want to use geometry to define the margins, but do not want to load thegeometry package otherwise. I have a little bit of a workaround by using \PassOptionsToPackage, but then the package is loaded even when the option is not selected and it changes LaTeX's default margins which I don't want to change in this default mode. Ideally, the textpos and multicol packages wouldn't be loaded unless the option is selected either, because they are otherwise unnecessary.

What is the most correct way of accomplishing this?

---

The custom package:

\NeedsTeXFormat{LaTeX2e}[1994/06/01]

\RequirePackage{graphics}
\RequirePackage{tikz}
\RequirePackage{libertine}

\pagestyle{empty}
\setlength{\parskip}{6pt plus 2pt minus 2pt}

\newcommand{\fullline}{%
    \noindent\rule{\linewidth}{.4pt}\\
    \vspace{-\baselineskip}\\
}

\newcommand{\stretchtitle}[1]{
    \vspace*{-5\baselineskip}\noindent\hspace*{-.75in}
    \resizebox{\dimexpr1.25in+\linewidth}{!}{\textsc{#1}}
    \vspace{\baselineskip}\\
}

\newcommand{\header}[1]{%
    \noindent{\sf\huge\\\\\noindent%
    \begin{tikzpicture}[remember picture, overlay]%
        \draw[right] (-.4em,.5em) node {#1};%
        \draw[line width=1pt] (-.4em,-2em) -- (-.4em,0em) -- (\dimexpr.4em+\linewidth, 0);%
    \end{tikzpicture}}\vspace{-1.25\baselineskip}\\\par\noindent%
}

\newcommand{\leveltwo}[1]{%
    \vspace{\baselineskip}\noindent{\Large\sf#1\normalsize\\\rule{.5\linewidth}{1pt}}
}

\RequirePackage[absolute]{textpos}
\RequirePackage{multicol}

\DeclareOption{compact}{
    \PassOptionsToPackage{margin=.62in}{geometry}
    \setlength{\columnsep}{18pt}
    \setlength{\TPHorizModule}{\paperwidth}
    \setlength{\TPVertModule}{\paperheight}
    \renewcommand{\stretchtitle}[1]{
        \newcommand{\titlewidth}{3.37in}
        \begin{textblock}{.88235294}(0.058823,0.045454545)
            \noindent
            \resizebox{\titlewidth}{!}{\Huge{\textsc{#1}}}\\
            \rule{\textwidth}{1pt}
            \normalsize
        \end{textblock} 
        \vspace*{.5in}
    }
}
\ProcessOptions\relax

\RequirePackage{geometry}

MWE for custom package use:

\documentclass[letterpaper]{article}
\usepackage{heavymodern}
\usepackage{lipsum}

\begin{document}
    \stretchtitle{Minimum Working Example}

    \header{Example}%
    \lipsum[1]

    \leveltwo{Second-Level Example}

    \lipsum[2]
\end{document}