Your friend has no idea what he's talking about, you answered the questions fine!

If I was an employer I'd want to hire someone who was confident and respectful, all of which those answers reflect about your personality.

I'd go ahead and use those answers, and disregard your friends silly remarks.

In my experience, I haven't been asked number 1. So, I don't really know what my response to that would be. Personally I just say what comes to mind and not really prep for it because your friend is right that it all sounds too generic. Most employers will ask you questions that more pertain to figuring out what kind of a person you are. What I mean by that, is a variation of number 3.

Instead of them asking why they should hire you out of all our applicants, its much more generalized in that they ask why they should hire you at all. Or in my experience has also been quite vague and been asked as "tell me about yourself". At which point in time I usually just make a joke and they usually ask something more specific like what i do in my spare time.

2. I've never been asked this question specifically, but a common variation of this question is "what do you do if you see someone stealing?" And I guess you have to answer that how you want to answer it, but mostly i'd just say you'd address it yourself, and if it seems to continue then you'd like the appropriate person know. You'd address that person not because you feel entitled to do so, but to just let them know your stance on the subject.

4. That is a corny answer. Just be honest other than saying that you desire more wages.

By making your answer so generic may entice some employers but most of the ones that know what there doing will look right by to someone who's more themselves and the type of people their looking for (phlegmatic clerics are usually the ones). But really anyway, unless you're willing to be unhappy at work because you've allowed the employer to give you more responsibilities that you're willing to take on just because you need a job, I'd really suggest you just be yourself in an interview and keep at it until you find a manager that the real you can get along with both professionally and informally

One of effective way of passing interview and interview question is to be yourself.. Believe me.. Employer do know if your lying or make things up, even if they believe.. it ends up bringing more expectations to you.. but its a good move practicing interview.. its just means your serious on the job.. anyway.. goodluck!!