Definitely the not-Headmasters according to Lord_Zed's comment with kup's amendment. TFormers.com also speculated on not-Computron -- probably because of the head to body ratio makes the 5 look like Causality-sized toys(?). However since FOC Combaticons, I prefer not a combiner team of 5 to be entirely made of the same size scale.

Also, Toyworld's doing not-Hardhead. Did FP and TW have a friendship going on? Hopefully FP or another third party group of the same calibre picks up not-Highbrow, otherwise I've still got RTS Highbrow as the out of character stand in