1) Can he send off the first batch of forms to Kentucky, without us being married yet, or should we wait till we've got married, then send off the paper work together. And would waiting this long disadvantage him?
I'm worried that he'll have to wait till late-June if we want to send them off as a married couple (the earliest we can do it with a 1 month waiting period, and bringing his parents over from inter-state etc).
I know that we have to inform the state department that we have gotten married in the interim, and that we'll have to prove our relationship is real etc, but I don't want his application to be disadvantaged because he submitted the forms late!
Sending the forms off in late-June is not too late, or late at all. They got mine in July and my case-number was in the low 700s. I got my interview and GC, no delay, no problems, no worries.
From other selectees' experiences I've read, it seems it is better to get married first and send the forms off as a married couple. Otherwise, your partner gets the GC then has to sponsor you as a wife, which isn't as easy or quick as the DV. Search the forum for those experiences. Just make sure you've got lots of proof that you've been a couple before selection - photos and documents.
2) Does anyone know the acceptance rates from past years for Australia specifically? I know that there are 125,000 are selected for further processing, and only 55,000 get selected, so it's obviously not 100% acceptance world wide, but I'd be curious to know how much that percentage applies to Australian applicants (if anyone knows!)
Total OC DVs issued in 2012 was 562; Australia's share of that was 292; out of 2,001 selected for the entire OC region.
In 2011, 578 for OC, and 275 for Oz; out of 1,600 selected. Highest for Oz was 331 in 2005, lowest was 99 in 2002.
Tiny when you think about it but there are some who apply on a whim, for a laugh, with no intention of pursuing it. Others change their mind. And others don't pass the interview for some reason or another. Not sure of those percentages, would be curious to know that.
3) And a last, and probably very basic question... what are all these batches that everyone talks about for interviews? Does anyone know if his 2014OC000023xx number is good/bad/doesn't matter?
Case-number is a better term for what you're referring to, if I understand correctly. "Batch" relates to them selecting a first batch of selectees, with notifications, but holding back some in case the uptake isn't what they expected. But it seems they've just selected one batch this time, so no point talking about batches anymore.
As far as whether your partner's case-number of 23xx is good or not - I don't think we'll know til August when they release the first cut-offs for October DV2014 interviews, to get an idea of how the numbers might progress.
Congratulations and Good luck!