In theory, eventually, you'll be able to comment from Mastodon and follow Kbin accounts and magazines from Mastodon. You can already make a magazine's profile appear on Mastodon, see screenshot below.
At the moment though, the main Kbin server kbin.social is so totally overwhelmed that they've had to activate a protection system called Cloudflare which prevents cross-platform federation working.
So, right now, you'd need to sign up on a Kbin server.