Yes, you're right dear. "Tuche" is rather for lackiness, "epitychia" for happiness, success.
Yes, I would change the word:
Ï„Ïχην--> á¼Ï€Î¹Ï„υχίαν (acc.)
ἡ αÏχή ἡ τῶν πάντων => ἡ αÏχή τῶν πάντων
I don't think there is a need for two "ἡ" before and after "ἡ αÏχή ἡ" ...
In Polish language it is called "szyk przydawki" (attributive order?), This repeated "ἡ" makes the attributive important as much as the subject is.
In Eglish it probably would be: The beggining of the whole things. So, I think that tis repetition is quite justifiable here...
Francky, I still think that the attributive order with repeated ἡ is correct (ἡ αÏχή ἡ τῶν πάντων ). This is a very often used order in Antient Greek.
I translated it into English not quite precisely. It should be rather:
The beggining - the one of the whole things.
the one --> this just beginning
The repeat places emphasis on "the beginning"(αÏχή)