Split multiple columns into rows using DAX

Hi,

I am not sure if I understood your question correctly, but please check the below and the attached pbix file.

Expected result table = 
VAR _t =
    GENERATESERIES ( 1, 100, 1 )
VAR _pathitem =
    ADDCOLUMNS ( Data, "@path", SUBSTITUTE ( Data[List of Students], ",", "|" ) )
VAR _pathitemsinging =
    ADDCOLUMNS ( Data, "@pathsinging", SUBSTITUTE ( Data[Singing], ",", "|" ) )
VAR _pathitemdancing =
    ADDCOLUMNS ( Data, "@pathdancing", SUBSTITUTE ( Data[Dancing], ",", "|" ) )
VAR _generatetable =
    FILTER (
        GENERATE (
            _t,
            ADDCOLUMNS ( _pathitem, "@Students", PATHITEM ( [@path], [Value] ) )
        ),
        [@Students] <> BLANK ()
    )
VAR _generatesinging =
    SUMMARIZE (
        FILTER (
            GENERATE (
                _t,
                ADDCOLUMNS ( _pathitemsinging, "@sing", PATHITEM ( [@pathsinging], [Value] ) )
            ),
            [@sing] <> BLANK ()
        ),
        Data[ID],
        Data[Class Name],
        [@sing]
    )
VAR _generatedancing =
    SUMMARIZE (
        FILTER (
            GENERATE (
                _t,
                ADDCOLUMNS ( _pathitemdancing, "@dance", PATHITEM ( [@pathdancing], [Value] ) )
            ),
            [@dance] <> BLANK ()
        ),
        Data[ID],
        Data[Class Name],
        [@dance]
    )
RETURN
    SUMMARIZE (
        ADDCOLUMNS (
            _generatetable,
            "@activity",
                SWITCH (
                    TRUE (),
                    COUNTROWS (
                        FILTER (
                            _generatesinging,
                            Data[ID] = EARLIER ( Data[ID] )
                                && Data[Class Name] = EARLIER ( Data[Class Name] )
                                && [@Students] = [@sing]
                        )
                    ) >= 1 && COUNTROWS (
                        FILTER (
                            _generatedancing,
                            Data[ID] = EARLIER ( Data[ID] )
                                && Data[Class Name] = EARLIER ( Data[Class Name] )
                                && [@Students] = [@dance]
                        )
                    ) >= 1, "Sing,Dance",
                    COUNTROWS (
                        FILTER (
                            _generatesinging,
                            Data[ID] = EARLIER ( Data[ID] )
                                && Data[Class Name] = EARLIER ( Data[Class Name] )
                                && [@Students] = [@sing]
                        )
                    ) >= 1, "Sing",
                    COUNTROWS (
                        FILTER (
                            _generatedancing,
                            Data[ID] = EARLIER ( Data[ID] )
                                && Data[Class Name] = EARLIER ( Data[Class Name] )
                                && [@Students] = [@dance]
                        )
                    ) >= 1, "Dance"
                )
        ),
        Data[ID],
        Data[Class Name],
        [@Students],
        [@activity]
    )