Apart from that minor "Let's create an infinite number of universes out of nothing" problem.
Mathematical solutions are never guaranteed to be physical, or even potentially realisable.
Mathematical solutions are never guaranteed to be physical, or even potentially realisable.
I tend to think of it like the number line. There are infinite numbers between 0 and 1. If we decide to define infinite unique ranges between 0 and 1, the space each one occupies becomes infinitely small and the total range is conserved.
But we don't know whether the multiverse is infinite or not, so that corresponds to the question of whether the range is from 0 to 1, or 0 to infinity.
Either way, the original point stands, and unitarity of the wavefunction (the most notable conservation law) is maintained in Many-worlds.
Where people get confused seems to be a mix-and-match of incompatible parts of the Copenhagen and Many-worlds interpretations, where you have both universe-splitting and the non-unitary wave function collapse in the same flawed interpretation.
I consider this scenario improbable.
No. The "pilot wave", in pilot wave theory, is a mathematical object identical to the universal wavefunction of the many-worlds interpretation. As such, if you believe that computation is all is required for consciousness to exist (and there's no separate "is real" tag on the math), then it's an incoherent concept.
I fall on that side myself, but I can't convincingly argue that it's the right philosophical stance to take. I've yet to see anyone give a proof, it just seems most likely.