I have given TOEFL (iBT) and got 112/120. Will TOEFL be acceptable to the Canadian authorities as a sufficient proof of English ability (enough to earn the full 16 points) or so I have to give IELTS as well?
If you claim proficiency through a letter then other tests may be used to support your argument. However, if you are showing your proficiency through IELTS, then IELTS is needed. Most people aer expected to do the IELTS.