As far as finding fights. That is one of the hardest things to do when making a highlight reel.
The best Fighter highlight reels are the ones that have some rare footages of fights. I personally dont have a DVD burner but i have some really olds fights on DVD and i want them ina Highlight reel so bad.
Your highlight reels were pretty good for the first ones. The hardest ones to do are about a single fighter. I found yours didnt seem to have a theme except maybe Pride fighters. The music in the first one was a good choice, but the second one not so much.
Its good to chop up songs in a highlight reel too. Take only the part of the song with the upbeat. That way rather than making a highlight reel according to a song you can make the song to the HL reel.
Here is a link to my last HL reel, Slam Time
I find the best way to learn how to make a HL reel is to watch others and figure out what works and what doesn't.
Oh and for fight footage. Try the www.mma-tv.net forums. They are known for having links to downloadable fights, or you can stream fights off the site.