Before adding the indexes resolve these implicit conversion warnings affecting your cardinality estimates and seeks.

PlanAffectingConvert ConvertIssue="Cardinality Estimate" Expression="CONVERT_IMPLICIT(nvarchar(100),[TP].[DocumentId],0)"

PlanAffectingConvert ConvertIssue="Cardinality Estimate" Expression="CONVERT_IMPLICIT(nvarchar(100),[FD].[DocId],0)"

PlanAffectingConvert ConvertIssue="Seek Plan" Expression="CONVERT_IMPLICIT(nvarchar(100),[TP].[DocumentId],0)=[D].[DocumentID]"

PlanAffectingConvert ConvertIssue="Seek Plan" Expression="CONVERT_IMPLICIT(nvarchar(100),[FD].[DocId],0)=[Expr1008]"

PlanAffectingConvert ConvertIssue="Seek Plan" Expression="[Expr1007]=CONVERT_IMPLICIT(nvarchar(100),[TP].[DocumentId],0)"

PlanAffectingConvert...