in my opinion you will need good gardener working with the builders team. It is first step.
The second step - after demolition - is gardening/landscaping.
If you know your expectations for the final design - let him know. Good gardener should be to deal with this issue.
Hope it can help
A landscape gardener is who you're after (best just to use one tradesman to do the lot). We do this type of work all the time. A builder may be able to do the work but probably wouldn't have the specialist knowledge to provide you with the best results.
I hope it all works out well for you.