I'll answer based on what I looked up on the internet.
1) Is Freeze dried food better than frozen?
Depend on the kinds and the purposes of using. Normally those expert would love to give their fish some frozen but they still need freeze dried as regular food. And you need to see what's the best for your fish.
2) Which is better, Blood Worms or Tubifex worms?
Tubifex, but actually both of them is not that good for adult fish. Why don't you try live brine shrimp instead? It's better for flowerhorn.
Or cyclop-eeze might be the best.