Davy, you can certainly assign the name with Javascript.
http://stackoverflow.com/questions/2004315/populate-1-form-field-based-on-another
I believe (test this before you trust it), that you can simply remove those fields from the Personal Information section, and XC will use the billing info instead. I have yet to check this myself, but I imagine that is how QT would do it.
Probably the Personal information section should not be used by default on new installs. Very confusing and frustrating to have these additional fields. We need to keep field entry to an absolute minimum. I have been investigating replacing Captcha with a fairly complex honeypot system, to be able to remove this bothersome step from checkout.