TN visa, job title, degree,

A few questions on TN visa application. In a hurry. Thanks a dozen.

1. I got my Bachlor of Engineering degree in Mechanics back in China,
2. then I attended a Canadian university and got a post degree certificate (not of any degree but just a certificate showing that I have successfully completed all the required courses) in computer science,
3. the job offer that I've got now, with a title of "Software Engineer".

My question is:
1.Do I need to show my B.Eng degree from China, My B.Eng is from Mechanical Engineering instead of from computer science although I have the transcripts showing a lot of computer courses
2. I have only translated copy of the B. Eng. sealed in an envelop, not "經過認證的學曆證明". Do I need one? where and how long can I get it.

2. Is "Software Engineer" a good title to apply for the visa?

Thanks again