\documentclass{article}
\usepackage{pgffor}
\newcommand\myfuncx[2]{\myfuncdoit#1:#2\relax}
\def\myfuncdoit#1:#2:#3\relax{ First: (#1), Second: (#2), Third (#3) }
\begin{document}
\foreach \p in {foo1:int,bar:float,baz:bool}
      { (\expandafter\myfuncx{abc}\expandafter{\p}) }
\end{document}