1/ Why do you think that so many Kenpo practitioners under Ed Parker jumped ship and enrolled at Bruce's Los Angeles school? People like Dan Inosanto, Larry Hartsell, Steve Golden, Jerry Poteet and Bob Bremer.
For many years there has been a misnomer that there was an exodus from Ed Parker's school to Bruce Lee's Chinatown school. This simply wasn't the case. Of the five you mention, Jerry Poteet and Bob Bremer weren't that far along in their training with Ed Parker, although it is true that Dan Inosanto and Larry Hartsell were two of kenpo's best students. While I don't know the actual numbers, I would suggest that there was an equal number of students who started with Bruce and later left to train with Parker.
2/ Did you ever witness Bruce Lee free sparring against other reknowned martial artists and what was the outcome of such matches?
Bruce Lee sparred with a number of renowned martial artists, most prominent around that time being Chuck Norris, Joe Lewis, and Steve Sanders Muhammed. He certainly made a respectable showing against anyone he sparred, at least to my knowledge, but I don't agree with those who believe that he was capable of defeating anyone. Unfortunately, Bruce didn't enter tournaments, so we'll never really know how he would have done. Personally, I feel he would have done very well in point sparring because of his incredible speed and ability to quickly perceive his opponent's weakness.
3/ What did Bruce actually teach you in the martial arts?
Bruce's expertise was working with black belts and didn't care for teaching beginners. To this end, he had an uncanny ability to point out what was wrong with someone's art. I talk about my personal reaction to him in the chapter entitled "Hollywood." What I found most instructive was his practice of placing one's strongest hand in front; the fatal move of crossing the centerline; and simplicity.
4/ Why do you think Bruce closed all his JKD schools?
Probably because they weren't making any money. This wasn't unique to Bruce's JKD schools. Historically, making a profit from martial arts schools has been an uphill battle for the vast majority of those who try. Chuck Norris, for example, sold his schools because they weren't turning a profit, and Ed Parker faced serious financial problems in the early 1970s.
5/ In your opinion, who are the toughest fighters that you have faced or have seen in your many years of martial arts?
My expertise and focus has never been fighting. While in my youth I entered tournaments, including the first Internationals, I never made it far enough in the elimination rounds to find myself up agains the like of someone like Joe Lewis or Chuck Norris - thankfully!
All the best