Hi Matthew, welcome at the Icehouse Jam! Thanks for thinking of your entry and sharing your thoughts ;)
We're excited to discover what you're going to do. You have seen indeed that we love Myst-like and 1st-person adventure games in general, so you'll have all our attention if you decide to make such a game! (of course there is no obligation to do this)
Thanks also for your support of The Five Cores Remastered: I'm sure Iridescent will be touched to see that you participate to our Jam.
Just a quick note regarding this: the members of the collective are just people who help each others in their free time, we're just an online group, a gathering of indie devs who share ideas in common - even though we try to make it "official". Everyone with a bit of motivation and skills can potentially join us, there's no contract to sign or things like that (we're not a publisher, there's no money involved, each Creator in the collective remains free and keeps his righs and ideas, etc). Of course we have to be careful to who is joining us in order to save our original "spirit", so it often takes time if we accept a new Member.
I was saying all that to make it clear that, by supporting Iridescend and The Five Cores on Kickstarter, you supported him and his game only (we want to be sure that people are not mistaken: we don't take any money from the KS of our members!). But it is true that helping one of us always has a good indirect impact for all the collective, so it is always great. That's also how we try to help each others! Giving exposure to one of our projects/creators will help the others too. I'm sure you understand.
Regarding the creation of your game, if you can use such an engine such as Unity I'm sure you'll make something very interesting. Most people in our collective who try to do Myst-like adventures with 360° views like Myst 3 Exile are using 2d engines like Adventure Maker or Dagon. If you have a way to do it in Unity (and know how to), you can be sure that we'll be very interested! Go ahead and surprise us :) Good luck!
And regarding the music of your game, you'll probably find people on our Discord or forums. Some of our Members are music composers (Python Blue and Yazorius). I don't know if they will be available for you (but they can't be available for all projects). But there will probably be other music composers. Recently on Discord someone named lincolnlogs introduced himself as a music composer available for this Jam, so that could be a good opportunity for you to try to contatc him? I can't tell more about him, he's not shared other info so far.
Don't hesitate to come join us on our Discord and/or forums to become officially a Friend of the collective, and who knows, little by little, week after week, you could become officially a Member that we will support and who will support us? :) Or it could be even faster if you win the membership in this Jam (it's one of the Prizes) hehe!
I hope I replied to your questions. Can't wait to see what's going to happen! From what I see on your site you have already solide bases in 3D and illustration. Let's keep in touch. Good luck for the Jam!