Canada Withdrawing 401K and Pension Plan

[US2Canada]

I have some funds in US 401K account and pension plan of the US company I worked with years ago. I migrated to Canada in 2012 and want to withdraw funds from my 401K and pension plans to support the down payment for an apartment.

I am willing to take the penalties and tax deductions as getting my first apartment is an important step of my life. However, I want to make sure I take advantage of the tax treaties between US/Canada, foreign tax credits, IRA rollover etc. to minimize the loss due to early withdrawals from the accounts.

I am looking on guidance on how to do this. So far I have this:

1. Rollover 401K and Pension Plan in an IRA account so there is only one account to deal with. This is only possible if I am able to open an IRA account while being a resident of Canada. Otherwise, I will have to cash out those accounts directly.
   
2. Withdraw funds from IRA and submit W8BEN to reduce tax withheld. Not sure what percentage would be withheld.
3. Transfer the withdrawn funds to Canada. Put up to $25K in RRSP and leave the rest in cash.
4. Take a loan of $25K from my RRSP towards my down payment and use the cash as well.

Can I do something better than the plan above?

Would I have to file taxes in US because of this withdrawal? If I do, would my Canadian income be considered for US taxing purposes?

Can I avoid the early withdrawal penalty because I am not a US resident?

I would appreciate any guidance you can provide!