ok seeing as your probability to be invited next round is over 90% you can do following:
1. Have all foreign PCC in hand (they will not expire as long as you will not return to that country before sending your application)
2. get Medicals done (also it can be done fast you might want to book appointment). Yes this one does expire, but with your invitation chances you can risk it.
3. Have all reference letters ready. Anything from previous employments does not expire anymore (as that document will only state what was happening in the past). As for your current employment it does not have to be fresh fresh (2 or 3 months old is ok). You can use bank statements to show that you got paid by that company recently in order to support that you still work there.
4. What you already have and should have is of course ECA (do not forget to have your original diplomas translated on hand as well) and language test.
5. And of course have a valid passport.
6. You can even go for proof of funds now (I doubt that there will be problem with 2-3 weeks old document).
So get all that, make scans, prepare PDF files and then once invited get ready to spend up to 3 hours uploading your application, cursing their database system, loosing some documents then uploading them again and then finally paying for all that and submitting it.
And the race does not end there. You need to get AOR (they are kind of automatic and issued just within hours) and immediately submit your BOWP application as well.
That must be done latest on the last day of your current work permit (to be safe before 3PM in Ottawa).
Good luck
