How soon does it switch from Administrative Processing to Ready to Issued? Is there a particular pattern we should watch out for as a sign that our visa application was approved?

One, there is no particular pattern. Two, nobody (even if they claim they can) will be able to tell you when you can expect your Visa Status to change on CEAC. Every case varies and you really don’t have any choice but to wait and check your status repeatedly for updates. No one should finalize…

The Consular Officer didn’t say if I was approved or not. They took my passport though, is that a good sign? Am I approved?

Neither. It’s not a good sign nor a bad sign. Them taking your passport is not (in any way) an assurance that you’ve passed your interview nor has anything to do with your visa status. There are other background checks that are still needed to be done before an approval / issuance of a visa. This…