While I applaud your initiative to give this a try, I STRONGLY suggest you not do it. Unraid is great for basic NAS duty in a business, as long as there is someone on staff to keep up with the maintenance. Relying on it for 24/7/365 uptime for services like VM's and dockers is not a good idea.
I personally run pfSense as a VM on Unraid, and 99.9% of the time, it just works, and is great. However... there is no way I could recommend selling that combination as a turnkey set it and forget it to a local business. It requires too much tinkering and attention to stay working well and securely. Gone are the days that you could set up a system and not update it for years and expect decent results. Now you have to stay on top of updates, and each update that is applied has a chance of taking down the system for a period of time until the resident tech can figure out what new tweaks need to be applied to get running again. If you are running their internet through a VM on unraid, you will quickly become their least favourite person when they have no internet and can't get a quick solution.