As 'smoke dodge' is a BS-attack, does it cause a F2F against a dodge? Does it change if the smoke template covers the enemy unit or not? Does it change if another unit is shooting the 'dodging' enemy too? EDIT: Noticed 'smoke dodge' only applies against enemy 'attacks', so presume 'smoke dodge' would be invalid against a dodge and therefore resolve to idle? What happens in a smoke dodge vs smoke dodge situation? would that be F2F as it's BS-Attack vs BS-Attack?
"Smoke Dodge" doesn't exist in N4. Smoke is just a BS Attack, with a special rule that says "Performing an Attack with a weapon with Smoke Ammunition allows the user to make a Face to Face Roll against all enemy Attacks that require a Roll and LoF, and whose LoF passes through the Zero Visibility Zone generated by the Smoke Template." So a Smoke BS Attack against a Dodge isn't F2F. Two Smoke BS Attacks, each of which would block the other's LoF to their target point on the table... might be F2F? They're BS Attacks which require a Roll and LoF (to the target point), so I don't see why not. It never comes up because if your opponent throws smoke and you don't want it to go down, you normally shoot at them to make a F2F and also potentially wound them. Throwing your own smoke to prevent their smoke wouldn't make sense, because even if you succeed, there's smoke on the table.
No, it wouldn’t resolve to Idle. Just like Reset vs. a normal ammo BS Attack doesn’t resolve to Idle—you only switch to idle when dealing with invalid requirements.
In the entry for Smoke special ammunition it specifically says that being caught in the area of effect means you get to make a normal roll against the Dodge skill. Otherwise, you're right, it would be FtF. There's a similar thing where if it weren't for the wording on MSV, directly throwing a smoke grenade at someone with MSV would create a FtF situation. I suggest reading the rules for Smoke carefully.