The truth is, Negan isn't all that lean. He's about the same as Rick
Rick, however, usually wears those button up shirts that bunch up at the waist. Negan, has a very form fitting leather jacket. It gives the illusion of sliming him down. I'd say he's actually probably a little buffer than Rick in reality. And people have made Rick figures on everything from Bruce Lee bodies to TTM 19's and all have looked right given the right clothes. I think a standard Truetype style body would work just fine. I think avoiding muscle bodies is really the only must here. Those typically don't have the double jointed elbows, and resting Lucille on his shoulder would be impossible to do without the double jointed elbows.
The height extenders may not be necessary either depending on how the boots are made.
