If you read Decoherence is Simple while keeping in mind that EY treats decoherence and MWI as synonymous, and ignore the superfluous references to MML, Kolmogorov and Solomonoff, then 1a) is addressed there.
If you read Decoherence is Simple while keeping in mind that EY treats decoherence and MWI as synonymous, and ignore the superfluous references to MML, Kolmogorov and Solomonoff, then 1a) is addressed there.