%%
%% http://tex.stackexchange.com/questions/299067/using-itemize-and-enumerate-at-the-same-time
%%
\documentclass{jarticle}
\usepackage{enumerate}
\usepackage{amssymb}
\usepackage{pifont}
\newcommand{\mynewitem}[1][]{\refstepcounter{enumi}\item[#1~\theenumi.]}
\begin{document}
\begin{enumerate}[{$\bullet$} a.]
\mynewitem[\checkmark] Right
\item normal item
\item another normal item
\mynewitem[\checkmark] Right
\mynewitem empty item
\mynewitem[\ding{55}] Wrong!
\item etc.
\end{enumerate}
\end{document}
