OS X Business Infrastructure

I have a client who is starting up a business who wishes to use nothing but Mac exclusively. This means desktops, tablets, and company phones will all be Apple devices. The starting number of users will be around 10 people, with hopes of growing to over 100+ employees in 3-5 years.

Under normal circumstances, I'd just set all this up using PCs and Windows so I can use Active Directory to manage user permissions and establish group policies that are pushed to each machine. However, that doesn't appear to be an option. I've integrated Macs into an existing Windows Domain and AD in the past, and I know how quirky it can be. It wouldn't make any sense to have a single Windows Server just for a flaky AD and Domain infrastructure.

I'm out of my element on this one, but can learn and adapt fairly quickly. I've done some reading on Open Directory, and it appears to be my best bet on setting up user groups as well as storing user information. Would OD essentially create a domain that would allow users to log in to any machine throughout the office? This would facilitate employee movements (promotions, office moves, etc.) without actually having to move the workstation (I prefer to keep all machines in assigned locations as it makes the inventory process quick and smooth). This would also mean that the average user would NOT be allowed to save directly to their machines, but would save to a main file server (or a "Home Drive") instead. This server would be backed up daily and whatever recommended redundancies would be put in place in case of a server meltdown or any other technical issue.

Another thing I'd like to facilitate is the ability for employees to access their files from wherever (say they wish to do some work from home, or are working on the road). In the past, configuring it so that users may access their "Home Drive" was clunky but has gotten much easier within the Windows environment. What are my options for this in a OS X environment besides having users just save to an iCloud account? Or is that the best, most robust way of doing things? Would a separate DNS server tied to the company's TLD (like server.exampleCompany.com) that acts as a gateway be an appropriate solution for this if the iCloud isn't used? Could the DNS and file/OD server be contained on the same machine, whether done via virtualization or actual static install? In case of employee termination or resignation, being able to access all of their files and retaining them for future use/review is absolutely crucial. Looking for suggestion from those experienced with a Mac-only enterprise environment.

The average user will likely be working from a 21.5" iMac, while the admins and supervisors will be running the larger 27" iMac, with perhaps a few iMac Pros for those who will actually need such computing power.

I've done my best to outline what the goal is, so I appreciate any input and feedback I can get.

Thanks!