Officially Steam is not included but they reserve the right to add it back. https://www.esafety.gov.au/about-us/industry-regulation/social-media-age-restrictions/which-platforms-are-age-restricted
As for gmail, I can't find a clear answer or even anyone who's asked the question. The whole account deletion thing is stupid, they should just remove all the safety consequences of having an account (limiting interaction, hiding public profiles, etc). Actually they should just make me e-safety commissioner, because I'd do a far better job.