Tag Guard
Gerrard and Co. are headed back to Dominaria as Mercadian Masques ends. Rath is uniting with Dominaria as Nemesis ends. Both sets take place at roughly the same time. Prophecy also takes place at the same time. So it is safe to say all the main characters from this block will be in Invasion (sans the ones that got killed). It is supposed to detail the Phreyxian invasion of Dominaria. All card rumors are undoubtably fake at this point. So, in short, not much.