\index inside \pagenote. How to propagate the pagenote number correctly?

Question

The following MWE is taken from \index inside footnote: How to propagate the footnote number correctly with index package? and used with the pagenote package. The index result shows: inside second pagenote, 2n0 instead of inside second pagenote, 2n2. What needs to be done to solve this problem?

\documentclass{report}
\usepackage{index}
\usepackage{imakeidx}
\usepackage[hidelinks]{hyperref}
\usepackage[page]{pagenote}
\newcommand\pn[2]{\hyperpage{#2}n#1}
\makeatletter
\let\if@nopnote\iffalse % just for the example
\newcommand{\is}[1]{%
    \if@nopnote
    \index{#1}%
    \else
    \edef\tempnumber{\thepagenote}%
    \expandafter\pagenoteindex\expandafter{\tempnumber}{#1}%
    \fi
}
\makeatother
\newcommand{\pagenoteindex}[2]{\index{#2|pn{#1}}}
\makeindex
\makepagenote
\begin{document}
First\index{First index} sentence.\pagenote{First pagenote.}
Second sentence with index inside pagenote.\pagenote{Second pagenote with index.\is{inside second pagenote}}
Third sentence.\pagenote{Third pagenote.}
\printnotes
\printindex
\end{document}

EDIT 1 - MWE

\documentclass{report}
\usepackage{index}
\usepackage{imakeidx}
\usepackage[hidelinks]{hyperref}
\usepackage[page]{pagenote}
\newcommand\pn[2]{\hyperpage{#2}n#1}
\makeatletter
\let\if@nopnote\iffalse % just for the example
\newcommand{\is}[1]{%
    \if@nopnote
    \index{#1}%
    \else
    \expandafter\pagenoteindex\expandafter{\tempnumber}{#1}%
    \fi
}
\renewcommand{\notenuminnotes}[1]{%
    \edef\tempnumber{#1}%
    {\normalfont #1.} }
\makeatother
\newcommand{\pagenoteindex}[2]{\index{#2|pn{#1}}}
\makeindex[program=xindy]
\makepagenote
\begin{document}
First\index{First index} sentence.\pagenote{First pagenote.}
\clearpage
Second sentence\index{sentence@\emph{sentence}} with index inside pagenote.\pagenote{Second pagenote with index.\is{inside second pagenote}}
\clearpage
Third sentence.\pagenote{Third pagenote.\is{sentence@\emph{sentence}}}
\printnotes
\printindex
\end{document}

The index entry for "sentence" lacks the pagenumber when using \makeindex[program=xindy], which is incorrect. But with \makeindex only, there are double entries of "sentence" in the index list, which is incorrect too. How can this be fixed?

EDIT 2 - Multiple Index with pagenote?!

Is there anyone knowing how to do this task also for multiple indexing like

\makeindex[name=things,title=Things,program=xindy]
\makeindex[name=names,title=Names,program=xindy]

I think the package pagenote needs here progression and development. A MWE could be:

\documentclass{report}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc}
\usepackage{comment}
\usepackage{index}
\usepackage{hyperref}
\usepackage{imakeidx}
\usepackage[page]{pagenote}
\newcommand\pn[2]{\hyperpage{#2}n#1}
\newcommand{\pagenoteindex}[3]{\index[#1]{#3|pn{#2}}}
\makeatletter
\let\if@nopnote\iffalse
\newcommand{\is}[2]{%
    \if@nopnote
    \index[#1]{#2}%
    \else
    \expandafter\pagenoteindex\expandafter{\tempnumber}{#2}%
    \fi
}
\renewcommand{\notenuminnotes}[1]{%
    \edef\tempnumber{#1}%
    {\normalfont #1.} }
\makeatother
\makeindex[program=xindy,title=Things,name=Things]
\makeindex[program=xindy,title=Names,name=Names]
\makepagenote
\begin{document}
WordOne\pagenote{WordOnePagenote-\is[Things]{WordOnePagenoteThings}}
WordTwoThings\index[Things]{WordTwoThings}
WordThree\pagenote{WordThreePagenote-\is[Names]{WordThreePagenoteNames}}
WordFourNames\index[Names]{WordFourNamenregister}
\printnotes
\printindex[Things]
\printindex[Names]
\end{document}
Thank you for attention and solutions.
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