Mil8 saidPresumably, changes to the UCMJ are part of the DADT implementation process.
Once it has been implemented, the repeal of DADT will be extremely difficult to reverse. I do not necessarily mean legally, but (as happened in other nations' armed forces) the change will cause so little fuss within the armed forces, that, within a few months of its being implemented, there will simply be no political capital in using it as a campaigning issue any more.
You are correct. This is what the current Republican House is trying to prevent from being implemented.
And to be technical, DADT will not need to be "repealed" because it will have become unnecessary. Once the underlying law making it illegal to be gay in US uniform has been changed, the matter of DADT becomes moot. You can say whatever you like about your orientation without fear of legal action against you.
And that's all DADT ever was, very similar to the Constitutional prohibition against self-incrimination. You didn't have to admit you were gay, nor could the military ask you. But if you were discovered to be gay, out you went. And that's still legally true to this day, though there's a "hold" on these actions until the matter is finally resolved.
Though even after the US Code is changed (it's in Title 10 if memory serves, but otherwise please correct me) I'd still like to see some order, Executive or otherwise, that says sexual orientation doesn't have to be revealed. There's no reason to track that, so let's hope it just never is asked again.