Actually this second question is a hard one that is not easy to answer because there are so many variables in volved.
For example, the Lum chinese is easy to open becasue :
- Good leverage on the blade
- smooth due to washers
- smooth due to perhaps less pressure on the blade from the liner.
Take now for instance a FRN endura:
- not quite as smooth as there is no washers
- leverage is good
- top lock now applies pressure against the width of the tang, so it will have a different feel from the Lum as it's lock pressure is against the side.
Now lets sat ATR:
- leverage + because of cobra hood
- washers so it's smooth
- heavy blafe though so it's a littler tougher to get started
- lock puts pressure on the side of th blade like the LUm.
So as you can see each knife will be just a little bit different. I there's probably no location that says, Oh this lock open easily because of blah, blah, blah. You have to take all these factors in to account to be able to understand what makes a blade easy and smooth to open.
This still doesn't address what lock is stronger. That's an endless debate. You can make broad generalizations but that's almost useless as it depends entirely on the execution. Some say framelock is best for example, but I ran across a $450 framelock that would slip when you applied a bit of pressure to the back of the blade. As you get more experience you'll realize those types of questions just don't have an answer.
You first question about what kind of locks there are is un answerable too because there is probably an infinite number of them. Though the previous list is a pretty good sample. Except for this correction:
frame lock (Chris Reeve Sebenza)