Snap Shot says initiative is treated as roll of 20 for surprise round but "may only take an attack action with a ranged weapon". Does that mean that if any attack is made, it must be with a ranged weapon, or does it mean that the only action you get at all is an attack action (specifically, one with a ranged weapon), and Ambush is worthless if you have or plan to get Snap Shot talent?
Snap Shot says initiative is treated as roll of 20 for surprise round but "may only take an attack action with a ranged weapon". Does that mean that if any attack is made, it must be with a ranged weapon, or does it mean that the only action you get at all is an attack action (specifically, one with a ranged weapon), and Ambush is worthless if you have or plan to get Snap Shot talent?
A surprise round typically allows you to get one standard or move action.
Snap Shot gives you a bonus to initiative for that bonus round, but limits your single action to a ranged attack.Ambush gives you a full turn's worth of actions in the surprise round.
Based on the language, they aren't going to work together. I'd tend to prefer Ambush, as it gives more options/mobility during your surprise round. Snap Shot is only going to be useful when you spot an ambush coming or someone else spots your ambush. It will be helpful, but is more situational.