Width and positioning of \bar, \hat and \tilde

Here is a solution using the accents package.

First, define the accent marks from scratch:

\newcommand{\newbar}{\scalebox{.9}[.85]{\trimbox{0pt .55ex}{\textminus}}}
\newcommand{\newtilde}{\scalebox{.9}[1]{\trimbox{0pt .6ex}{\textasciitilde}}}
\newcommand{\newhat}{\scalebox{1.5}[.75]{\trimbox{0pt 1.1ex}{\textasciicircum}}}

The arguments in \scalebox control the width and thickness respectively. For example, if you want the bar to be thicker, increase the [.85] in the \newbar command. To make the bar less wide, decrease the {.9}. The \trimbox command comes from the trimclip package. It is needed to accommodate whitespace (vertically) around the accent marks. The nonzero argument controls the height of the accent mark above the symbol. To raise the accents, trim less. For example, to raise the bar, decrease the .55ex.

Once the accents are defined, they are called using the commands

\newcommand{\stretchedbar}[1]{\accentset{\newbar}{#1}}
\newcommand{\stretchedtilde}[1]{\accentset{\newtilde}{#1}}
\newcommand{\stretchedhat}[1]{\accentset{\newhat}{#1}}

Here is the complete code:

\documentclass{article}

\usepackage[T1]{fontenc}
\usepackage[p,osf]{cochineal}
\usepackage[varqu,varl,var0]{inconsolata}
\usepackage[scale=.95,type1]{cabin}
\usepackage[cochineal,vvarbb]{newtxmath}
\usepackage[cal=boondoxo]{mathalfa}

\usepackage{accents}
\usepackage{trimclip}

\newcommand{\newbar}{\scalebox{.9}[.85]{\trimbox{0pt .55ex}{\textminus}}}
\newcommand{\newtilde}{\scalebox{.9}[1]{\trimbox{0pt .6ex}{\textasciitilde}}}
\newcommand{\newhat}{\scalebox{1.5}[.75]{\trimbox{0pt 1.1ex}{\textasciicircum}}}

\newcommand{\stretchedbar}[1]{\accentset{\newbar}{#1}}
\newcommand{\stretchedtilde}[1]{\accentset{\newtilde}{#1}}
\newcommand{\stretchedhat}[1]{\accentset{\newhat}{#1}}

\begin{document}
$\bar{e},\hat{e},\tilde{e}\quad\bar{y},\hat{y},\tilde{y}\quad\bar{A},\hat{A},\tilde{A}\quad\bar{\Omega},\hat{\Omega},\tilde{\Omega}\quad$

$\stretchedbar{e},\stretchedhat{e},\stretchedtilde{e}\quad\stretchedbar{y},\stretchedhat{y},\stretchedtilde{y}\quad\stretchedbar{A},\stretchedhat{A},\stretchedtilde{A}\quad\stretchedbar{\Omega},\stretchedhat{\Omega},\stretchedtilde{\Omega}\quad$

\end{document}

If you will need the symbols in sub/superscripts you will need to use \mathchoice. Combine the macros as follows:

\newcommand{\stretchedhat}[1]{\mathchoice
{\accentset{\scalebox{1.5}[.75]{\trimbox{0pt 1.1ex}{\textasciicircum}}}{#1}}
{\accentset{\scalebox{1.5}[.75]{\trimbox{0pt 1.1ex}{\textasciicircum}}}{#1}}
{\accentset{\scalebox{1}[.5]{\trimbox{0pt 1.2ex}{\textasciicircum}}}{#1}}
{\accentset{\scalebox{.8}[.4]{\trimbox{0pt 1.3ex}{\textasciicircum}}}{#1}}
}
\newcommand{\stretchedtilde}[1]{\mathchoice
{\accentset{\scalebox{.9}[1]{\trimbox{0pt .6ex}{\textasciitilde}}}{#1}}
{\accentset{\scalebox{.9}[1]{\trimbox{0pt .6ex}{\textasciitilde}}}{#1}}
{\accentset{\scalebox{.7}[.8]{\trimbox{0pt .7ex}{\textasciitilde}}}{#1}}
{\accentset{\scalebox{.5}[.6]{\trimbox{0pt .8ex}{\textasciitilde}}}{#1}}
}
\newcommand{\stretchedbar}[1]{\mathchoice
{\accentset{\scalebox{.9}[.85]{\trimbox{0pt .55ex}{\textminus}}}{#1}}
{\accentset{\scalebox{.9}[.85]{\trimbox{0pt .55ex}{\textminus}}}{#1}}
{\accentset{\scalebox{.7}[.7]{\trimbox{0pt .65ex}{\textminus}}}{#1}}
{\accentset{\scalebox{.5}[.6]{\trimbox{0pt .75ex}{\textminus}}}{#1}}
}

You can adjust the spacing and sizing to your liking.

$\stretchedhat{e}_{\stretchedhat{e}_{\stretchedhat{e}}}$
$\stretchedbar{e}_{\stretchedbar{e}_{\stretchedbar{e}}}$
$\stretchedtilde{e}_{\stretchedtilde{e}_{\stretchedtilde{e}}}$

Note that you must \protect these if you want to use them in \section, \paragraph, etc. There is a workaround for using hyperref with \texorpdfstring in the comments.