> Acc to Cone 'aaraddha' as a past passive participle can also be from
> aa + rajjhati, and can mean 'accomplished', 'achieved', 'pleased',
> 'satisfied'.
> Could any of these senses fit in the translation of the passage in question?

Yes, that makes much more sense - how about this:

yoni cassa aaraddhaa hoti aasavaana'm khayaaya
/a beginning/and for him/made/is/of the taints/for the destruction/
"and a beginning for him is made towards the destruction of the taints."

Best wishes,

Yuttadhammo