I live in my first home and pay mortgage for it. I am planning to take HELOC on my first home and use it as downpayment to buy a second come. Then I am planning to make second home as primary residence and rent my first home.

1. CAn both mortgage (first and second home) be tax deductible?
2. Can the HELOC interest on first home be claimed as expense against the rental property?
3. Is there any other benefit in doing so? or any issues in doing so?

Thanks in advance for your help/advise