Well it sounds like you're planning on operating under your own magical ruleset - which makes sense if that's what's available, but unless I've been missing regular classes on how it actually works is probably going to leave a lot of people somewhat in the dark about what they're agreeing to or volunteering for. What does creating a timeline look like? Is every aspect of it laid out deliberately during the creation or is it pulling anything from our subconsciousness? What are the limits of how it's populated? Presumably less complicated lifeforms like plants are possible or it wouldn't be very habitable, but would we be able to create sentient, self-aware life, up to and including other people? Would they be advanced facsimiles of life or fully realised individuals? You're essentially asking for help on an advanced physics research project without explaining things like gravity or the speed of light.