Setting up SFDC Person Accounts after the initial sync has been completed
We did our initial sync between SFDC and Marketo without doing the proper setup for them in SFDC in our sandbox. I have since recreated the marketo fields on the account, but I don't have the option to map them. Is this something that can be done after the initial sync? Or do we have to start over?

We also have a custom object that is related to the person account via a lookup. I can see the object is "sync enabled" under the salesforce objects sync in the Admin menu, but we don't see the object when we look at the record in the lead database.
I am brand new to Marketo, thank you for any help that you can provide.