15 letters Inviting danger ... the end of which can precede each half of the answer to each asterisked clue Answer: PLAYINGWITHFIRE
15 letters He played a Nazi in "Marathon Man" and a Nazi hunter in "The Boys From Brazil" [Connecticut] Answer: LAURENCEOLIVIER
15 letters Author who created the characters named by the starts of 17-, 24-, 49- and 61-Across Answer: LOUISAMAYALCOTT
15 letters He conducted the premiere performances of "Pagliacci" and "La Boheme" Answer: ARTUROTOSCANINI
15 letters Overly inventive ... or a hint to the answers to 17-, 26- and 42-Across Answer: TOOCLEVERBYHALF
15 letters Rough estimates ... or what the ends of 17-, 24-, 52- and 65-Across are? Answer: BALLPARKFIGURES