BCA, Bank Central Asia has always provided the best, up to the minute accurate exchange rates
I can also vouch for that.
Regarding the rest, I also don't want to get into Notaris vs Lawyer, but I would suggest you propose a staggered deposit structure to minimize your exposure and only once everything's in the bag (i.e. the notaris / lawyer is about to file the change of title), you deposit (from euro's) to rupiah to the specified account - preferably to a 3rd party (i.e. the notaris / lawyer's "trust" account) - i say "trust" account because i have little faith in indonesian "trust" law.. in fact, i don't believe it exists, so you'll be relying purely on a private contract for the handling of those funds..
Best of luck - you're doing the smart thing by asking first in any case..
Ct
