Accounts::AccountID = Events::AccountID
Events::AccountID = MasterTracking::AccountID (enable allow create for MasterTracking)
Accounts::AccountID should be an auto entered serial number. The other AccountID fields should not be auto-entered serial numbers.
If a record in Events has the account ID: 1234, and you've defined a Name field to use a looked up value field option to copy from a field in Events, then creating a new record in MasterTracking and selecting, or entering 1234, should cause the value to be looked up and appear in the name field.
Your relationships don't look like they are set up right here. The relationships will only work if you have one Events record for each Accounts record and that seems unlikely. I think you should either have this relationship:
Events::EventID = MasterTracking::EventID with Events::EventID defined as an auto-enter serial number
or Mastertracking should link directly to the accounts table instead of events.
The values you are looking up: Name, Invoice#, etc do not look like values that should be looked up. Looked up value settings should only be used when you need to copy the current value of a field from the look up table and don't want that value to change when the value in the lookup table changes at some future date. A classic example is to use Looked up value fields to copy the current unit price from a products table in to the line item entry of an invoice. When the business owner changes prices, the new invoices should copy this new value, but existing invoices should not show a change in value. In your case, once you have workable relationships, you can likely just include the fields from the related table directly on your layout instead of using looked up value settings to copy the values.
Here's a thread that may help you sort this out. It discusses both approaches and how to implement them: