I represent Rookies E-solutions, which is a web development company. We have developed many websites similar to your requirements. We have developed websites using PHP, .NET, and many other Content Management Systems like Joomla, Wordpress, Magento, and Drupal.
Before delivering the project, we do rigorous testing which includes Alpha, Beta, Unit, Integration and System Testing.
First of all, the design of the website is sent to client for approval. After the approval, a team of designers work on to implement the HTML, but for Joomla, templates are used with some corrections and design tweaks. During the design phase, you can ask for unlimited number of changes, until you are satisfied with it.