No.  If you are eligible for Medicaid you cannot be eligible for marketplace subsidies.  Some people who receive UI benefits will be eligible for Medicaid, in part because Medicaid will NOT take into account the $300 per week federal supplemental UI benefits.

Yes.  Generally, people must have an annual income at least as high as the federal poverty level in order to qualify for marketplace subsidies.  In states that have not expanded Medicaid eligibility, that leaves poor adults with no access to financial help for health coverage.

Possibly not.  A general rule says that people are not eligible for marketplace subsidies if they are eligible for a job-based plan that is affordable and meets standards for minimum value.  See these FAQs for more information.

Yes.  When you file and reconcile your 2021 federal tax return, you will be able to collect the increased premium tax credit as a refundable tax credit.

The higher premium subsidies are in effect for the 2021 and 2022 plan years.  For premiums you already paid in 2021, before the new law passed, you can claim the increased tax credit when you file your federal income tax return.

For HealthCare.gov, the increased premium tax credits should be visible by April 1, 2021.  Current marketplace enrollees can log in and update their applications to get new results starting on that date.