I just took your last DDL and replaced the final select with this

SELECT Distinct ROW_NUMBER() OVER(PARTITION BY re.AthleteGuid ORDER BY a.DateOfBirth DESC) AS rn,

r.Guid as RegistrationID

,a.Guid as AthleteID

,a.Firstname as FName

,a.LastName as LName

,a.Gender as Sex

,a.Address1 as Addr

,a.City

,a.[State] as ST

,a.Zip

,a.MedicalConditions as Medical

,a.Email

,a.DayPhone

,a.EveningPhone

,re.USATNumber

,re.TShirtSize

,re.Division as Div

, CASE r.PaperRegistration

WHEN 1 THEN 'Paper'

ELSE

CASE r.PayByCheck

WHEN 1 THEN 'Check'

ELSE 'CC'

END

END as Paytype

,e.Name as [Event]

,r.Date as RaceDate

,TotalFee

,r.OnlineFee

,_rl.relay

FROM #Registration r

INNER JOIN #RegistrationEvent re ON re.RegistrationGuid = r.Guid

INNER JOIN [#Event] e ON e.Guid = re.EventGuid

INNER JOIN #Athlete a ON a.AccountGuid = r.AccountGuid AND a.Guid = re.AthleteGuid

--LEFT JOIN RegistrationDiscount rd ON rd.RegistrationGuid = r.Guid

LEFT JOIN #RegistrationRelayLeg rrl ON rrl.AthleteGuid = a.Guid

--LEFT JOIN #RegistrationQuestion rq ON rq.AthleteGuid = a.Guid

--LEFT JOIN RegistrationAdditionalFee ra ON ra.RegistrationGuid = r.Guid

CROSS APPLY

(

SELECT

CONVERT(NVARCHAR(MAX), rl.LegName) + ',' AS [text()]

,CONVERT(NVARCHAR(MAX), rl.Name) + ',' AS [text()]

,CONVERT(NVARCHAR(MAX), rl.MedicalConditions) + ',' AS [text()]

,CONVERT(NVARCHAR(MAX),Convert(varchar(10),rl.DateOfBirth, 101)) + ',---' AS [text()]

FROM

#RegistrationRelayLeg rl

WHERE

rl.RegistrationGuid = r.Guid

ORDER BY

AthleteGuid

FOR XML PATH('')

) _rl (relay)

WHERE TotalFee > 0

and r.RaceGuid='04010abc-83dd-4aaf-abb1-0177eac5d562'

I think that gets what you want, but it is hard to say for sure.