Hello @KaileyMcCourt ,
Assuming the "Marketing ID" is your own identifier and as these are new they won't have UUID or MID associated with them.
You can still upload them into AAM via offline file ingestion and qualify traits but they won't be available in reports. These IDs can be stored in AAM prior to the ID sync and once these IDs are synced in AAM, you will start seeing data in your segments.
You would need onboarded traits, cross-device datasource and offline files.
I hope this gives some direction to the mentioned use-case. Happy to further discuss this!
Regards
Ankita Sodhi