Hi Pico,
Yes all papers you are using as evidence need to be notified.
If you are going to send copies of Documents (diplomas, certificates, transcripts, etc) they need to be certified. If the original documents are in English, I am pretty positive you can mail them all to your family to be certified in your home country. If in another language , you will need official translation.
Ok, now about the ''less important documents'', you can have them notified by asking a staff from your university to sign and date them or a former employer, when applicable. For example, I asked my course director to sign the copy of my final thesis; lecturers to sign presentations. In all cases, I also asked for a short declaration saying that ‘I’ have done such paper/ presentation. (It also included their position at the time, the subject, the number of pages- if applicable, and the date it was presented.)
So, having all those documents/papers set in your portifolio, I believe the lawyer will only be necessary to sign that page (39 – Statutory Declaration) from the application form.
Having a notarization body from your home country and a lawyer from Canada to deal with your documents should not be a problem to the NZ Board.
If by any chance, the Board does not accept one or other document, or if incorrect, they will let you know by sending a letter and it will give you sufficient information to do it right next time. So, do not get frustrated if that happens, it seems quite common...