I love seeing Aaron's work within the Rust community. I had the pleasure of studying under his father and his family's gifts are clear in both their work.
Are metapackages going to be available for others to utilize? If so, how will conflicts be resolved if packages require two different versions of the same package?
Yes, metapackages are intended to be a general cargo feature, available to all. I suspect the design has not progressed far enough to definitively answer your question about conflict resolution, but I'd imagine you have to override that dep explicitly to fix it.
Are metapackages going to be available for others to utilize? If so, how will conflicts be resolved if packages require two different versions of the same package?