From what I know, there are over 160 different English/Japanese cards for Latios and Latias combined
It makes for a smoother game overall and works incredibly well under various stax effects, which notably makes for a great sub-theme, and Heliod is overall one of the best mono-white commanders
The player pays 2000 Life Points to activate it, then counts each turn that passes, starting with the turn when Final Countdown was activated as the first one
This is a bit less efficient, but the effect is actually not noticeable: each Mimic Vat activation will create a number of usable damage triggers "for each Clash of Realities", instead of "for each Clash of Realities TIMES Doubling Season", since all the triggers for the copies are put on the stack at the same time with no opportunity to act in between to increase the number of triggers that might be created
Dark Coffin (and to a lesser extent Statue of the Wicked) is creative way to get the most out of Hunting Grounds