NightFlightsAreMagic
You wil get one "aptitude" test - either the Wombat Test or the traditional Cathay aptitude test. It depends on which of these you did in Stage 1; if you did the Wombat in Stage 1 you will get the traditional test, and vice versa. There is only one panel interview, it will last around an hour in which general and technical questions will be asked.
The English Test will come in Stage 3, which should be held on the day following Stage 2. You are invited to Stage 3 only if you pass Stage 2.
My Stage 2 invitation e-mail was a little different from yours. It specifically said I would do the Wombat in Stage 2, and did not include the medical. The e-mail mentioned nothing about the Stage 3 schedule, so naturally it said nothing about the ICAO English test or Management interview either. You should only get a tentative Stage 3 schedule on the day before you do Stage 2.