With regard to 1) show them the CRM Implementation guide. All CRM needs to do is create a few security groups in AD. If the AD owner still won't relent then ask them to create the required groups and then install CRM using the command line option and a config
file (all explained in the Impl Guide).
2) You need writes to create objects in AD if you are running the install wizard. The SQL job error sounds like a customization of your SQL Server that automatically runs back ups for new databases. CRM doesn't create such a job. I'd speak to the SQL Server
DBA about this.