The Fantastics on MGM, Deram, Bell, and Bus Stop were Jerome "Romey" Ramos (lead), John Cheathom, Donald Haywoode, Richard Pitts, formerly of the R&B Group The Newtones on Baton and the Soul Group The Strangers on WB. Ramos, Cheathom and Haywoode were formerly of the R&B Group The Velours on Onyx, Cub etc.
The Fantastics on Impressario, Copa & SS7 were Jethro V Caldwell (lead, Willie Parnell (second lead), later of Archie Bell & Drells; Eddie Webb, later of Masters of Soul; Bobby Williams.
There is a Fantastics on DMD the Detroit group Robb refers to and another on Hit.
above courtesy of the Soul Harmony Singles (not always 100% accurate before you have a go at me )