最近色々提出書類が変更になり大変だと思いますが、自分で翻訳して無事審査が終了し移民になれたという方の例はまだ聞いた事がないのでリスクが高すぎると思いますよ。
IDENTITY AND CIVIL STATUS DOCUMENTS
A marriage certificate, birth certificate, Family Register or certified official copy and a translation of your unaltered "Koseki Tohon" and "Kaiseigen Koseki Tohon" (all
names in the register, even the ones that have been removed due to death, marriage, change of residence, etc) including details of your birth, marriage and divorce (if any)
must be submitted. All names of your family members, even the ones that have been removed due to death, marriage, change of residence, etc., must be included. The translation should be in English or French and done by a certified translator.
東京・カナダ大使館サイト
http://www.canadanet.or.jp/i_v/im/fcqa_e.shtml
Question: Can my sponsor or myself translate the documents we will submit with the application?
Answer: Translations should be done by a professional translator.
多少費用は掛かると思いますが時間は節約されると思うので、上記ガイドに書かれてる通り、プロの翻訳家に頼まれた方がベターなのでは。