Hi Brietmax,
vRA does not handle the management of dns records (create/destroy/update.)
For this, you will have to use an event subscription to call the appropriate workflows that you create (ie. ABX, vRO)
For our environment - we have instituted it via vRO workflows which call a powershell script that will create/delete records based on the lifecycle event. We are still using a proxy WinRM host to run the powershell as it uses the dns management cmdlets. There's lots of example scripts out there for managing DNS records with powershell that you could base yours on.
If using the AD integration within vRA, then I believe it will always create the computer object for a compute resource no matter which os/image you use. The OU is defined on the project level.
This just didn't work for us either - so we made the AD:Computer vRO object a custom resource within vRA and then we provision it within the blueprint only if the OS of the image is Windows. Having it as a managed custom resource works well for us, as the computer object will also be removed on destroy.
Hope that helps some.