Please excuse this interruption, but don't those four principles belong to the teaching of Shin shin toitsu do, i.e. the Tempukai?
I don't think they are usable to teach aiki like used in aikido or daito ryu?
And I don't think, Ueshiba osensei ever used them?
There are only 27 dojo of ki aikido all over Gemany and they follow a certain Yoshigasaki sensei. They don't claim to use "aiki", but try to just use "ki". Which is different.
So the way of using aiki / ki musubi and connecting using atari which I try to learn, simply doesn't exist in their aikido.
So I think those four principle are simply not designed to teach what for example Daito ryu calls aiki?
IMO, the proper understanding and implementation of those four principles will help establish a coordinated mind and body, which is required as a foundation to build aiki on.