OK... IEC visa can not be extended from what I know.
But - before your IEC visa runs out ( 30 days before normally), you could ask for a change of visa - and ask for a visitor visa ( it costs 75$ and can be done online). Include proofs that you are applying for PR soon ( if you have paid the fee for the application, include the receipt for example, so you can show that you are serious about applying for PR), and most likely you will be granted a visitor visa for 6 months. It gives you time to work on your application.... and get everything together. Not sending some documents is not going to help, because you might have your application sent back because of documents missing ( especially some like birth certificate etc ).
It takes about 90 days to get an answer, and until you receive an answer, you are under "implied status" - so you can stay in Canada. I would not advise to try and leave the country, and come back, but as long as you are in Canada, you'll be fine.
ALso - I'm not sure why you would go the inland route, and you might have a very good reason, but just for you to be aware : you can apply outland AND stay in Canada. It won't give you implied status like Inland does, BUT as long as you maintain your visitor status, then you would be OK. With a danish passport, it should be a problem. You could get your first visitor visa now (and stop working as soon as your IEC visa runs out), and extend it another time if your PR didn't come through at that point....
You don't have to apply inland because you're in Canada - you can apply outland, it's legal, and "advised" by CIC even if you are in Canada if you can get faster processing time. As you are a danish national, you would go through London, and it's a pretty fast VO.... so you could have your PR in the same time it would take you to get the first stage approval for Inland ( currently 6 months).
Also - with inland, you HAVE to stay in Canada for the whole time ( 14 months at present). Which means, no holidays trip, and no emergency trip for family reasons etc - if you leave Canada and not allowed back in ( the border officer can see that you have applied inland and you're not supposed to leave, so he can refuse you entry for that), then your application will be abandoned, and you would have to start all over again, outland.
There are very few advantages for visa-exempt applicants to go inland if they have a fast VO, and London is definitely one of the fast ones... so just wanted to mention it to you - a few people assume that they have to go inland because they are in Canada but it's not the case.
Good luck,
Sweden ( eller Sverige!

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