I see no evidence of any delay in the new tests.
Where there is some delay (perhaps) is that
SOAS, the institution hosting the tests in London, will only be offering it in December. It's such a major production for them that I'm not that surprised. They had a cap on the number of candidates last year as well. I can only hope that they will offer twice yearly tests in the future, I'm sure the demand is there.
Maybe the only way to expand the tests outside of Japan is if enough people contact their local exam centres to ask about July tests.
I doubt you could ever sit two tests back to back. The tests just take too long for one thing (there's a lot of waiting on the next part to start too) and there is also a slight paranoia involving the test papers.
The best you can do is apply (and pay) for two levels then make your decision about which to take on the day.