Sounds like 1 is just a question of using a nice Markdown / WIYSIWIG-plugin, 2 comes down to a website theme ... that leaves point 3 which I can understand is a non-easily-replaceable feature.
Why is this step necessary? mastodon.xyz might not be the server where you are registered, so we need to redirect you to your home server first.
Don't have an account? You can sign up here