Fillable PDF, read-only when send via Adobe Sign

I have to questions: 

1. I've designed  a fillable PDF that is used as a template and then sent to Process Owners to be signed.  Unfortunately the document is editable by the Process Owners. Is there a possibility to make the fields read-only once sent for signatures? 

2. After signing a document via Adobe Sign, I'm getting two documents. The signed document and the audit. When someone is editting the prefilled document before signing, there are no information about changes made in the document in the audit file. Shouldn't this information be included or is there a way to include this?

Any help appreciated! Thanks a lot!