Basically every single one of your points here is answered within the recent Cardano Effect podcast on pledge.
You also fail to mention that we will clearly see several operators begin to join together to pledge a competitive stake, this will be something set by the pool operators totally independent of ao. also post-Voltaire Cardano the community will certainly vote on all variables (ao, k,…) so it really does not matter long term what these are set at for shelley mainnet (with obvious discretion to the market conditions observed during the ITN).
Finally I think it’s super misleading to use the RUST ITN build to compare that to the Haskell spec they have been working on/produced several peer-reviewed research papers on since 2017. Anyone reading IOHK’s work on incentives was very well aware of these variables (as well as the obvious point that they will likely be tweaked/changed based on market conditions/community vote).