All of the Batman Beyond Wave 1 figures were made by Fred Aczon.
Terry was made from a Dmitri figure from the Anastasia line and head from a power armor Batman Beyond. Dmitri's arms were cut off below the shoulderjoint and repositioned. The jacket, neck, and bulked shoulders were epoxy putty.
Modern Joker was made from the Wildcard Joker repaint. The hair and face was dremeled off and rebuilt with epoxy putty. The shirt was lengthened and jacket shortened also with the aid of epoxy putty.
Ghoul was made from a TNBA Riddler figure. The shoulders were dremeled a bit, and hat, hair and clothes were made from epoxy putty. The hat brim was cut from cardboard.
Bonk was made from a Batman Beyond Happy figure torso, and legs from a Detective Batman. The feet were cut off at the ankles and replaced with the boots of the Happy figure. The rest is epoxy putty.
Dee Dee twin pack
The Deedees were made from the torso of a Supergirl figure and legs from a happy meal version of Frollo from the Hunchback of Notre Dame. The heads were made from Sculpey and the legs and boots were shaped from epoxy putty. The belts were rubberbands. DeeDee#2 has the right hand of a Harley figure.
Many thanks to our photographer Fred Jr!