You just need to read a parameter from the URL:
String accountId = ApexPages.currentPage().getParameters().get('id');
Which you then place into the URL:
To make it ...
You can't edit the Name field; it is a compound field that uses FirstName, MiddleName (if enabled), Last Name, and Suffix. You need to edit the individual fields, instead.
DML operations will not update Child records in the records whihc you pass to it,
So you need to create another list for Net_Prospect_Score__c object and update this list.
Also you need to add another ...