Don't know to be honest regarding the TA, I do know that WM1A/Z is inadequate. I mostly focussed on Ananda as I want a portable solution, realistically at these price points you need to listen for yourself. Off the cuff Arya has the greater detail retrieval and Ananda is more musical, personally I prefer the latter and again Ananda is far easier to drive and combined with Hifiman's own R2R2000 a very compelling setup.
In short I'd say Arya is more suited to critical listening and Ananda more to enjoyment, equally don't take away that Ananda is lacking in resolution or detail retrieval, just different.
Q-6