Snap shot and opportunist

Ship moves has no tokens you snap shot take stress add die.

I believe adding dice counts as modifying, so no. That being said, if it does work, having a ship with wingman nearby would work really well.

Yes you can. Adding dice to roll is not modifying, adding results is.

You can do it on A-wings (presumably green squadron pilots).

Yep, that combo works. Adding a die before you roll is not modifying.

Only ship that can do it right now is A-Wings though.

Yes,

But could you have posted it here? -> https://community.fantasyflightgames.com/forum/293-x-wing-rules-questions/

Yes, but the only ship you can ever do it on is an A Wing with the title at the moment.