“Star Wars” creator George Lucas and his wife, Mellody Hobson, were the buyers who paid $11.2 million last year for Citadel founder Ken Griffin’s 66th-floor penthouse in Streeterville’s Park Tower building. Lucas and Hobson plan to combine the penthouse with their existing full-floor condo on the 65th floor of the same building — which they purchased for $18.75 million in 2015 — to create a 16,000-square-foot duplex penthouse, according to a building permit application recently filed with Chicago building officials.