Round 1:
https://www.behindthename.com/bb/game/5381088
Links are just a suggestion
S1’s SO: FN is top ten in Ireland
https://www.behindthename.com/names/tag/top_10_in_ireland / MN is an often-shortened name (ex: Genevieve, Edward) / LN is often spelled with double letters, but isn’t in their case
S2’s SO: FN is related in some way to Black history
https://www.behindthename.com/names/tag/black_history / MN has saintly associations
https://www.behindthename.com/names/description/saint / Has a hyphenated LN
S3’s SO: FN starts with X, Y, or Z / MN is a common Italian name / LN ends in s