The various wave 2 Legacy toys that did NOT have a release date, have been released by Amazon Australia... but it looks like they are being forced to adhere to the release dates of the rest, even though they are already hitting stores that don't care about release dates.
Core class
Shockwave and
Gen2 Megatron.
Voyager class Soundwave (clean deco Siege toy) - this one didn't have a release date or pre-order listing, so it was available for purchase a few days ago, which means that Amazon Australia definitely has the case-mate Jhiaxus as well, but while it has a release date of August 15th, they won't risk releasing it early unless instructed to by the supplier (Hasbro).