This is much clearer now, thanks.

Your 3-of-5 scenario, while certainly making it very difficult to steal the coins, also makes it too easy to inadvertently lose access to them. In many of your "loss of 2" situations you are depending on either a third party service (Gmail/FinalMessage) or a human's memory to recover your coins. Both of these are far from guaranteed.

There is also the important question as Loyce pointed out of where the seeds for all your hardware wallets are being stored, as these devices can fail.