Add builder hat to other people with tikzpeople

You could misuse one of the (unused) accessories:

\documentclass{article}
\usepackage{tikzpeople}
\begin{document}
\begin{tikzpicture}
\makeatletter 
\tikzpeople@builder@definecolors
\let\tikzpeople@person@paintshield\tikzpeople@builder@painthat
\node[alice,shield,minimum size=1.5cm] at (0,0) {};
\end{tikzpicture}
\end{document}

Ok, I managed it by taking a closer look into the files of the tikzpeople package.

To define a new combination (builderalice in my case) you need to define a new file tikzpeople.shape.builderalice.sty where you combine the parts and the according colors. Then you need to call \tikzpeople@declareshape{builderalice} (as it is intended to not be called from outside and contains an @ you need to wrap it in \makeatletter and \makeatother).

\documentclass[tikz]{standalone}
\usepackage{tikz}
\usepackage{tikzpeople}
\usepackage{filecontents}

\begin{filecontents}{tikzpeople.shape.builderalice.sty}
\newcommand{\tikzpeople@builderalice@paint}{
    \tikzpeople@person@paintshirt
    \tikzpeople@alice@paintshirtdetails
    \tikzpeople@person@paintrighthorn
    \tikzpeople@person@painthead
    \tikzpeople@alice@painthair
    \tikzpeople@person@paintgoatee
    \tikzpeople@person@paintlefthorn
    \tikzpeople@person@painthalo
    \tikzpeople@builder@painthat
}
\newcommand{\tikzpeople@builderalice@definecolors}{
    \definecolor{shirt}{RGB}{253,156,40}
    \definecolor{undershirt}{RGB}{232,232,232}
    \definecolor{skin}{RGB}{148,60,19}
    \definecolor{hair}{rgb}{0,0,0}
    \definecolor{hat}{RGB}{238,175,0}
}
\end{filecontents}

\makeatletter
\tikzpeople@declareshape{builderalice}
\makeatother

\begin{document}
\begin{tikzpicture}[]
  \node[builder,minimum size=1.5cm] (T) at (-1,0) {};
  \node[alice,minimum size=1.5cm] (N) at (1,0) {};
  \node[builderalice,minimum size=1.5cm] (A) at (3,0) {};
\end{tikzpicture}
\end{document}

This seems to be an XY question. What you might be really looking for is the TikZlings package in which you can add the accessories at will.

\documentclass[tikz,border=1mm]{standalone}
\usepackage{tikzlings}
\begin{document}
\begin{tikzpicture}
 \owl
 \thing[tophat,scale=1.5,yshift=-0.6cm,xshift=-0.05cm]
 \begin{scope}[xshift=2cm]
  \bear[magichat=violet,
   magicstars=yellow!80!brown]
 \end{scope}  
\end{tikzpicture}
\end{document}