I don't know of any developer produced on a non-profit basis that contains a chelating agent to prevent hard water cloudiness.This includes all Crawley's published formulae, PMK Pyro,the Pyrocats. Gainer's PC-TEA etc.I have not come across any grumbles on the internet about cloudiness produced by these developers.My guess is that manufacturers include a chelating agent because it is easier to sell a developer that produces a clear solution in hard water.So IMO chelating agent is interesting but not necessary in a non-profit developer.

I once wrote to Geoffrey Crawley re glycol in developers and he replied IIRC that he put some in his commercial developers to help prevent freezing in winter,evidently he considered glycol not harmful to the developing properties.

Re metaborate and TEA , IMO it would be interesting if a recommended non-crystallising metaborate formula could be found for those who only have metaborate not TEA.But at this time your work does seem to suggest that TEA might turn out to give a result closer to Xtol if this line is pursued.