Those are a lot of great questions @Davm! The answer to most of them are "it depends".
As you do more you will learn how much pear shading you need to do for a given spot but in general, unless its a very tight spot or you are using the pear shader a bit outside of what they are used for, you should walk it. Whether you use a mallet or are able to press hard enough is up to you and the application.
Again, usually, the camouflage tool gets used afterward to hide the edge of the work, camouflaging it up to the border.
Beveling is still a bit tricky for me and I don't rightly know all the answers. Sometimes you bevel both sides of the "V" but most times you need to look at the work and think about the depth and then decide which side should be dipping under the other and then bevel accordingly. Remember, it's all about establishing the depth so whatever needs to be brought forward should be beveled to look that way. As far as how far away from the cut goes, you want the toe of the beveler in the cut. Regarding angle, in most circumstances you want the tool as perpendicular to the surface as you can keep it. As you gain more experience you'll know when you can and should get away with angling the beveler to suit the application.
If you haven't seen @immiketoo's video on beveling on YT, you need to. Search for "cut less, bevel more" and you will get some wisdom.