Hi Sheonran87,
Your English language test must be valid to make you eligible to be nominated or stay in EE pool. That being so, if your IELTS scores expires before you get nominated, then be sure to provide another test result. If it does not, then you may not need to worry to provide another test scores to them. But bear in mind that once you are nominated and issued an ITA, you are also expected to be eligible to accept the nomination and proceed. So that means that if you are nominated and you accept it in EE and your IELTS is still valid, you have it. But if you are nominated and afterwards, your scores expires before you get ITA, you become ineligible. English language proficiency is one of the key areas they access candidates for their ability to settle in Canada. Your projection of 1st week of March to get nominated is ok, but it can come earlier than that. As they are on May applicants now(precisely 14 May), so when they resume by Jan 5 or so, they may be able to enter June and early July depending on the volume of work on ground. Nevertheless, to be on a safer side, you can sit the IELTS again and perhaps with a better score this time and get ready for your PR stage incase my permutation of early nomination by February doesn't holdsway. I am July 21st applicant and I am expecting to get AOR between Jan-March, 2016. My IELTS scores will expire by March 15, 2017. And also, your passport, ECA etc must also be valid at the time they invite you to apply otherwise, you would need to update your profile on EE with your latest documents.
All the best
