Do I have the right to distribute a modified GPL-v2 product under my own brand/authorship?

Question

Licenses for software and other works

The point is simple. There is a product that is distributed under the GPL-v2 license, the project has become of little interest to the author and he rarely releases updates, does not fix critical vulnerabilities, etc. My colleague and I made regular edits and we formed our own fork. Can we:
1. Distribute a product under GPL-v2, but under our own brand and name?
2. May we indicate that we are the authors.
3. Are we required to indicate that our product is a fork and is based on another product.
4. Do we have the right to sell premium (more perks for the user) versions of such a product?
5. Can we change the license type?

Thank you.

Answer 1

1. Yes.
2. Only add yourself to the authors. A complete list of authors must be required.
3. No.
4. If they are written by you - yes.
5. Almost impossible.
Read the text of the license and all questions will disappear.

Answer 2

only for users of Bolgenos
in the norms of the world - everywhere code, license and authorship