Where was this person entering from, all they can really do is send them back to where they came from, can they force them to go back to America if they didn't arrive from America?
Some offices won't issue one until after your first 90 day report, and of course you need to have a TM30 filed in their jurisdiction for them to supply the certificate.
Look at the Jakarta embassy website and look at their processing times. I'd have the course date start a month to 6 weeks from your visa application date. Do you buy a visa to Bali? Regardless, you'll have boarding passes and hotel reservations. They'll want proof you're there, get creative, don't go through the electronic gates.
The primary DTV holder will show the funds, the dependants/spouse will apply after the primary holder receives their DTV visa number and reference it in their application. The primary holder will also write a sponsorship letter to guarantee financial support for the spouse and dependants. The embassy might want to see 500k plus 500k for the spouse sponsorship, but unlikely for the children. Use the group search tool with those embassy keywords to read what others have reported about seasoning.