As mentioned ad infinitum. No you cannot join alpha users at this point in time. August 25th was the last day you could buy into alpha access. After that it looks like you can only obtain Planet Coaster via Steam, which has 2 editions: Normal and the thrillseeker edition.
Early Birds can no longer be obtained. Which means the current alpha group is final. Making it all the more exclusive.
Everybody else (including me) will have to wait until november.
Other pre-development perks have also been scrubbed. No VIP passes possible, except the ones you can win with these conditions
- have a google account
- watch the streams (with the lovely hosts Bo and Ed)
- responed in chat to their demands (for example by naming your favorite item from the workshop (or stream)
- get lucky