Split items in an Array in PowerBI

>The other columns in the table ... show up as null... How do we preserve the remaining fields as they are ?
I couldn't reproduce the described behaviour. Below is the sample I experimented with. Columns ResidentID, Name and EntryTimestamp do not hold any nulls.

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("fZHNCoJAFIVfRWY9xj2j498TFGSb2qmLQYwgcGERRPjuaUoUHdvMMB93hnO+KQoFEVFarZu2u2svd915OBkxxgd8xAdEmdhMklUamUSCcTYcl0epbqXKinkvpzuS+oJS9foXG46DAVe9qvQrCoaXNxfnau3tXedOn1lSliWwi1kgNMuISZYRBxyHHFuOI45jjpOv+mYok9fbxh21t3PXk2vfAmThM+wfAeACwAWACwAXAC4AXAC4AEwCCE4phnDMW8LMcqsn", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [ResidentID = _t, Name = _t, EntryTimestamp = _t, OverallHealthScore = _t, DaysWatchWornMonth = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"ResidentID", Int64.Type}, {"Name", type text}, {"EntryTimestamp", type datetime}, {"OverallHealthScore", Int64.Type}, {"DaysWatchWornMonth", type text}}),
    #"Parsed JSON" = Table.TransformColumns(#"Changed Type",{{"DaysWatchWornMonth", Json.Document}}),
    #"Expanded DaysWatchWornMonth" = Table.ExpandRecordColumn(#"Parsed JSON", "DaysWatchWornMonth", {"v"}, {"DaysWatchWornMonth"}),
    #"Expanded DaysWatchWornMonth1" = Table.ExpandListColumn(#"Expanded DaysWatchWornMonth", "DaysWatchWornMonth"),
    #"Expanded DaysWatchWornMonth2" = Table.ExpandRecordColumn(#"Expanded DaysWatchWornMonth1", "DaysWatchWornMonth", {"v"}, {"DaysWatchWornMonth.v"})
in
    #"Expanded DaysWatchWornMonth2"

>2. Will it be possible to add additional Array fields to the sample dataset and decouple them together ?
In the sample I povided now there is only one column that decouples. You can decouple other columns as well, why not.