Smart lists currently can't be extracted via the API. You can use either Get Leads by Filter Type or Get Leads by List ID to extract them from a static list.
Sorry, no, I just need the raw request and response from your call. I don't need your access token or munchkin id. I suggest you edit your post to remove both of those. Thanks.
You'll want to use two separate filters here. First using In Future After 120 days, and second, In Future 121 Days. That will capture whomever has a dates 120 days from now.
For this specific case you should just use the $TriggerObject. When you set the campaign up with Opportunity Is Updated as the Trigger, then the updated opportunity will be provide...