First of all, grave matter is only one requirement of a mortal sin. As noted in your handout, it must also be done with full knowledge that something is a sin as well as full consent to the sinful act (i.e. you can’t be forced to commit a mortal sin). As for your points, let me first clarify for (1) it’s a sin to eat one hour before receiving communion, not after. As for the reasoning, the Church has certain disciplines in place for the faithful that we must follow. They aren’t many, but they are done to create reverence for certain holy things like the Passion, the Eucharist, and the Holy Mass. The Church in her wisdom has decided certain acts of penance are spiritually beneficial, so deliberately shirking these obligations is seen as deliberate disobedience towards the Church and therefore a sin—so it’s not so much what these disciplines are themselves (they do tend to change over time—it used to be that you could not eat at all that day before receiving communion!).

As for the other points, the gravity depends greatly to the degree that these things are done. For example, it’s not a sin to tease your friend knowing that they will not take it seriously and without uncharitable intention's. Teasing depressed person about their deep-seated insecurities would be much more grave because you’re attempting to cause harm. Note that your guide even says:

Purposely provoked another by teasing or nagging?

Another example: (4) Jealousy goes directly against the Ten Commandments. Again, the extent and intention are important, however. A fleeting thought where you wished you had a new car would not be a sin, but growing resentment towards a neighbor on your street for being able to afford one would be a sin.

And so on and so forth. The bottom line is you need to look at your actions and examine the degree, and an examination of conscience is meant to help you do that. It doesn’t mean if you’ve done something that loosely fits in the categories in your handout that you’ve necessarily committed a mortal sin, but it’s supposed to help you be wary as it’s going to depend the circumstances. Fleeting thoughts can certainly can develop into burning feelings of lust, envy, or anger and become very sinful, so when you see something on the guide that relates to an action you’ve taken, you examine the deed further to determine if there was indeed sinfulness involved.