I am using the outlines package for multi level lists according to the second answer here since it was a pretty good solution and worked very well so far. However, I am wondering if it's possible to specifically have checkboxes if I change the command \2 or \3 to something like, say, \2c or \3c. Having the boxes on the right at the end of the line is preferable but it's OK even if it's the label or beside the label. If I were simply using enumerate, I could just do this but I am not sure if it's possible to tailor it to the outlines package. An MWE, although not too helpful in this case probably, is given.
\documentclass{book}
\usepackage{outlines}
\begin{document}
\begin{outline}[enumerate]
\1 This item should not have a check box beside it
\2 This item should not have a check box beside it
\2 This item should have a check box beside it
\3 This item should have a check box beside it
\end{outline}
\end{document}

If you want checkboxes beside all of them without choosing specific ones, is it possible to just redefine something and make the
– Zack Fair Jun 11 '17 at 15:08\1, \2, \3themselves produce the whole document with boxes?\1,\2,\3are defined only within theoutlineenvironment, that means there is no way of redefining them globally. One would have to alter theoutlinedefinition, but I don't know an easy way to do that. – Tiuri Jun 12 '17 at 07:18Cafter the\, right? – Zack Fair Jun 13 '17 at 09:41