8. God. How true!
Kali does translate very well into knife fighting, which is in fact where it originated, from what I understand. The Filipinos are some of the most accomplished knife fighters anywhere. Besides, stick work teaches you a lot about movement and leverage that work for you in other areas of MA as well.
I don't think any other arts are more or less useful than BJJ in terms of multiple opponents. However, BJJ comes into its own only on the ground, which is a disadvatage when faced with more than one person. Unless, you can throw a person without yourself going to the ground, in which case you've bought yourself some time to deal with goblin B. When combined with some stand-up skills BJJ is much more effective. However, given the choice between learning BJJ and a stand-up art, I would choose BJJ every time. Statistically, most fights end up on the ground anyway. (I'm talking about street-type fights which last more than a few seconds) So why not play the odds? Besides, I found it easier to learn grappling first then work on striking, though some may disagree. Ideally, you should be comfortable at all ranges of combat (I'm not) so as to be able to not "have to" depend on a fight occurring at your favorite range. That being said, I favor BJJ and related styles more because, paradoxically, proximity is security to you the grappler (in the absence of an edged weapon of course) because you can control his arms and legs, "weapons" if you will, by virtue of being in contact with them, whereas at punching kicking range, you don't have control of them (I never saw much catching the person's fist or their kick in midair unless the receiver was accomplished at trapping). In practice, I found that the range went from kicking to boxing-trapping (ranges 5 and 6) to grappling VERY quickly, unless both people were willing to keep the match at that range, so I found that ground skills were the best bet overall, though one shouldn't neglect standup. Strikes on the ground are always good. They don't even have to be hard. What I found is that a top position against someone who doesn't know better is good because any strike will get them to turn away, setting up an easy choke. The guard is an excellent defensive position (from which you can attack somewhat), but I wouldn't use it in a fight unless I had no other choice.
Psychology is the essence of all conflict (look at Skorzeny's sig!). All you have to do is make the aggressor see absolutely clearly that the cost of their actions may very well exceed the potential benefits, which is illustrated by your friend's story with the razor. Why do ya think Hitler never invaded Switzerland?
P.S. and someone who could grapple would have broken the football player eventually. It just points to the fact that you can't always expect the fight to occur at the range you like. Not much room to kick on the ground, so be ready!