Need to apply for reseller certificate in USA, do I need to open LLC and have EIN before applying for the reseller certificate

Hi Alan, I am planning to to online Amazon Arbitrage (FMB) if you are familure with this business model, I will:

1# open Canadian corporation, 2# Open Amazon seller account in Canada (Amazon.ca)
3# List items on Amazon.com, sell to US customer,
4# After sale order placed on Amazon.com, I will buy online clearance items from US suppliers (like WalMart/ Sam’sClub)
#5 WalMart will ship it directly to the US address.

Question please:

1# as mentioned in the subject, can I apply for reseller certificate, so WalMart verify that I am B2B and exempt charging me sales tax?
2# Do I need EIN, open LLC to apply for this certificate?
3# If the answer no need for LLC, then I will include my business profit in my Canadian tax return, is there any need to file income tax return with the IRS?

Thanks
Adam