Power Query : removing duplicates and merging duplicate rows selectively into one

For the sake of easy understanding of the code, I have written the power query step by step. But you can combine several steps and make the query much denser.

let Source = Table.FromRecords(
        {
            [id = 1, date = #date(2018,2,3), b = 513, c = 423],
            [id = 2, date = #date(2018,5,1), b = 534, c = 432],
            [id = 2, date = #date(2019,1,18), b = 345, c = 5434],
            [id = 3, date = #date(2019,2,2), b = 354, c = 4534],
            [id = 4, date = #date(2019,4,6), b = 543, c = 544],
            [id = 5, date = #date(2019,5,5), b = 654, c = 432]
        }
    ),
    
    ChangeColumnTypes = Table.TransformColumnTypes(Source,
        {
            {"date", type date}, 
            {"id", Int64.Type}, 
            {"b", Int64.Type}, 
            {"c", Int64.Type}
        }
    ),

TempTable = ChangeColumnTypes,
ResultTable = ChangeColumnTypes, 

MinDate = (x as table, y as number ) as date => List.Min(
    Table.Column(
        Table.SelectRows(x,each Record.Field(_,"id")=y),
    "date")
),

MaxDate = (x as table, y as number ) as date => List.Max(
    Table.Column(
        Table.SelectRows(x,each Record.Field(_,"id")=y),
    "date")
),

AddIsFirstDateColumn = Table.AddColumn(ResultTable,
        "IsFirstDate",
        each Record.Field(_,"date") = MinDate(TempTable,Record.Field(_,"id"))
),

AddIsLastDateColumn =Table.AddColumn(AddIsFirstDateColumn,
        "IsLastDate",
        each Record.Field(_,"date") = MaxDate(TempTable,Record.Field(_,"id"))
),

getFirstValue = (x as table,y as number) as number => List.Min(
    Table.Column(Table.SelectRows(
        x, each Record.Field(_,"id")=y and Record.Field(_,"IsFirstDate") = true
    ),"b")
),

FirstValue = Table.AddColumn(
    AddIsLastDateColumn,"FirstValue",
    each getFirstValue(AddIsLastDateColumn,Record.Field(_,"id"))
),

getLastValue = (x as table,y as number) as number => List.Min(
    Table.Column(Table.SelectRows(
        x, each Record.Field(_,"id")=y and Record.Field(_,"IsLastDate") = true
    ),"c")
),

LastValue = Table.AddColumn(
    FirstValue,"LastValue",
    each getLastValue(AddIsLastDateColumn,Record.Field(_,"id"))
),

RemoveDuplicates = Table.SelectRows(LastValue,each [IsLastDate] = true),
RemoveColumns = Table.RemoveColumns(RemoveDuplicates,{"IsLastDate","IsFirstDate","b","c"})
in
    RemoveColumns