1. Before importing the data, define the primary key field as an auto-entered serial number. After importing this data, still define that field as an auto-entered serial number but then do a show All records and use Replace Field Contents with the serial number option to number them and also update auto-enter options.
2. To copy the correct value to the correct record in the child table requires FileMaker (or a person for that matter if you were to do this "by hand".) to be able to tell which record in the child table matches to a given record in the parent table. It would appear that name fields are your only option for this. If so, you can go to Manage | Database | Relationships, click on the box (Tutorial: What are Table Occurrences?) for the parent table and use the duplicate button to make a copy of it. Link this copy by all three name fields to the table occurrence of your child table.
You can now go to a layout for the Child table, show all records and use Replace Field Contents with the calculation option to copy over the Value of the field you to which you gave a serial number value in 1. above.