-The face near Mordred's armpit looks like it could be Salieri or I guess Dantes, but the mouth make me think Salieri. -There's a corpse underneath Scathach's giant fish that could be Fergus. -There's another corpse inside the mouth of said giant fish, with an arm sticking out that might be Lancer. -Above Tesla's falling body, there's two characters with their faces covered that could be Assassin, and either Emiya or Amakusa Shirou. -There's a pair of muscular legs above Mashu's shoulder as well that I'm not sure about.
The buttocks just above Mashu's right shoulder (left to us viewers) with the black underwear.. maybe that's Maid Alter? Would make sense as she's a swimsuit servant also. Unless the artist went with a strict ''one version of any character'' rule.
AchillesIskandarFergusCu ChulainnCursed Arm HassanAtalantaMordred (Swimsuit Rider)ShielderLeonardo da VinciFujimaru Ritsuka (female)Fujimaru Ritsuka (male)Artoria Pendragon (Swimsuit Archer) Tamamo CatMarie Antoinette (Swimsuit Caster)Elizabeth BathoryGilgameshScathach (Swimsuit Assassin)Francis DrakeNero ClaudiusFlorence NightingaleNitocrisFouCleopatraJulius CaesarOzymandiasEdward TeachJaguarmanJack the RipperNursery RhymeHans Christian AndersenJeanne d'Arc Alter Santa LilyWilliam ShakespeareArtemisAlteraEuryaleAsteriosMedjedOrionNikola TeslaEdisonAstolfoBilly the KidRomulusSasaki Kojiro?MerlinAmakusa Shirou/Archer?Salieri/Dantes?Caligula