One solution would be to allow creating dummy objects. These would sit in the game, they might even be visible to player, but nothing in-game would count them for any purpose.
This could take care of things like delayed triggers.
For
Tetravus, however, the situation is a bit more complicated.
Tetravus, the way it's written, can sacrifice any Tetravite the permanent has previously created. And there are scenarios when a permanent creates a Tetravite without knowing that it will need to remember later who created it. They are pretty convoluted, but might involve, for example (if we pass on
Artificial Evolution Shenanigans):
I have
Death-Mask Duplicant,
Soul Foundry, Mizzum Transreliquat and
Tetravus. I copy
Death-Mask Duplicant with Mizzium, removing
Chameleon Colossus from my graveyard. Then I copy
Soul Foundry, which allows me to make a copy of Colossus. Then I permanently copy
Tetravus, and at the beginning of my next upkeep, I should be able to sacrifice the copied Colossus (as it has all creature types, including Tetravite).
So, the only solution I see right now is to make tokens always record which object in the game created them.