1. Yes, 2. Yes.

1. If you are not a Canadian PR or citizen, you do need a Canadina visitor visa.
2. Your travel to Canada within 30 days can benefit from Automatic Visa Revalidation using your valid I94 to re-enter US. But this is because of the flxibility of the border custom, so be careful about any changes. Normally, if your old visa stamp stands for a different status with your current H1B, you'll need a new visa. So, enjoy your trip and be careful.