The scope of Indian CA is as good as an accountant and no more than
that initially i.e. untill one completes his/her CPA/CA from Aus. CA
with ISA seems to have better response in IT audits.
Difficulty is very subjective word and being a CA you'll undersatnd
that. So how difficult it is really dependent on individual. But one
thing per my personal opinion is that it's less rigorous than ICAI's
CA.
Estimated costs should be collected from ICAA and/or CPA Australia's
webite (Refer to useful sites topic within this group)
Per my knowledge there is no activity by ICAI in Melbourne (but we can
think about initiating some)
Regards,
Shashi