Hi Jan,
You will have to prereg as a designer beforehand, which you can do here:
https://www.dexposure.com/m2018i.htmlNo matter what state your game is in, you can bring it, but we will need a description before the event. We've literally had people bring in games at all stages of production. Once, someone brought in two pieces of hand-written paper to talk to people about how to develop their game properly! So don't worry if you're not production ready.
The schedules for playtests are completely customized based on a phone call that you'll get sometime after you preregister. Right now we're organizing the panel schedule, and we'll fit you in around things that you want to attend.
Players who sign up to play in your game will get the opportunity to prereg for events and sign up at the event if it's not full.
For hotel room sharing, we don't do anything officially, but you can post here on our forums, or join the fan-created Facebook group and ask there:
https://www.facebook.com/groups/METATOPIAfans/