Gen 6 and Gen 7: Are all PID + Nature + IV + EC value + date combinations possible?

[gamecubefan74]

Are all PID + Nature + IV + EC value + date combinations possible for Pokemon from Gen 6 and 7?  I want perfect legendaries, but don't feel like I can RNG them. I was wondering if all value combinations are possible so regardless of what I input, it's possible to be generated by the game on real 3DS hardware?

[theSLAYER]

I guess before we get to that, the question I wanna ask is: is the date met generated upon meeting or upon capture? I suspect the latter.

because that easily breaks date and PIDIV. With this method you can change the date to whatever date that is legally allowed by the 3DS, after you encounter the Mon.