1) It is a rather foundational paper that is still absolutely relevant. Work in a field doesn't simply become dated because a certain number of years pass. Wigner's friend is far older, and last year I was at a conference on that specific thought experiment (Encapsulated Agents in Quantum Theory: Re-examining Wigner’s Friend) which, incidentally, discussed in some detail the 2018 paper in Nature Communications by Frauchiger & Renner where we find (unsurprisingly) the paper I attached cited as a standard reference on the many-worlds interpretation.I agree with you in the fundamentals of QM, but your reference to the 'Many Worlds' is a bit dated.
2) Much of the more recent work has become a muddle due to confusions over decoherence and spontaneous collapse combined with Everettian-type interpretations. Additionally, many of the newer solutions to the problems with probabilities in no-collapse theories like the MWI (much more serious than the preferred basis problems) involve subjective probabilities (see especially the recent work on this by Wallace extending the decision-theoretic approach of Everettian agents by Deutsch). Even Vaidman has acknowledged that i) probability remains the most serious flaw in any MWI approach and ii) there is no way to solve this issue that doesn't involve our own subjective experiences.
H. D. Zeh puts it best, perhaps:
"The multi-universe interpretation of quantum theory (which should rather be called a multi-consciousness interpretation) seems to be the only interpretation of a universal quantum theory...that is compatible with the way the world is perceived." (italics in original)
Zeh, H. D. (2000). The problem of conscious observation in quantum mechanical description. Foundations of Physics Letters, 13(3), 221-233.
It isn't. Recent research in the past decade has, in fact, shown the opposite, e.g.:Observations called randomness in the behavior in Quantum Mechanics is a problem of the limited human perspective, and more recent research is beginning to show this apparent randomness is not so random, understandable and predictable.
Acín, A., & Masanes, L. (2016). Certified randomness in quantum physics. Nature, 540(7632), 213-219.
Colbeck, R., & Renner, R. (2012). Free randomness can be amplified. Nature Physics, 8(6), 450-453.
Gallego, R., Masanes, L., De La Torre, G., Dhara, C., Aolita, L., & Acín, A. (2013). Full randomness from arbitrarily deterministic events. Nature communications, 4(1), 1-7.
Likewise in the case of the fundamental limitations in terms of the subjective nature of quantum theory as seen in e.g.,
Proietti, M., Pickston, A., Graffitti, F., Barrow, P., Kundys, D., Branciard, C., ... & Fedrizzi, A. (2019). Experimental test of local observer independence. Science advances, 5(9), eaaw9832.
That's how they are defined. The laws are based upon symmetries (usually of the Lagrangian but one can derive them even from Galilean relativity let alone other action principle frameworks) and the subsequent conservation principles, and these do not hold in general but rather for isolated systems (also generally for closed, but one can constrain open systems in thermodynamics and statistical physics or in frameworks similar to those in these fields to be more general).I do not believe we have yet defined the limits of 'physical laws which hold strictly only for closed, isolated systems to the universe' in part because we have not defined the limits of our universe.
Which reference? I gave several. Also note that in recent years (in quantum information and quantum computing especially) free choice has become key in many theorems and derivations.I disagree with your reference concerning determinism and 'Free Will.' (freedom of choice?)..