Need Clarification (Please Help)

I’ve done a UML diagram, but there are a couple of things I’m unsure about.

  1. If we have a system where the user has to Login, do we then have to include that use case for all the other use cases?

Example: In the system boundary I have the administrator instructor(as an actor). He must first login(use case 1). Then he can add or remove trainee (so use case 2:add trainee , use 3:remove trainee , right?). So in this kind of situation, do I need to draw an include stereotype from the add trainee, remove trainee use cases to the Login use case?

Please note that I have a link (association) between the instructor and the Add trainee and Remove trainee use cases. At first I had only the link between the actor and the login use case. Then The login use case was connected by an include stereotype to both Add trainee and Remove trainee (this I think is wrong). Can anyone clarify as I’m confused please?

  1. I have two other actors; coach and trainee. They also have to login. In the question it states:“The trainee logs in”. And later it says something for the coach. What is confusing is that in the question it says something like this:“The coach has another login page”. The word “another” makes me wonder if I need a seperate login use case for the coach. The trainee and the coach use the web to login. Whereas the admin uses a desktop program. So I’m thinking I need three seperate use cases(true?).

The way I’m thinking to do it is to have, one login use case, then seperate this into two (trainee and coach) using generalization, where Login is the base use case. Another question right here:

  1. When seperating into two as in the situation above, do I use to includes or extends stereotype, or use generalization?

Also I have lines crossing over each other, is that okay?

Sorry for the long list of question, but I have almost completed this, but I need some clarfication on these questions before I submit this.

Thanks in advance and I appreciate any feedback.