I haven’t tried this but technically it should be fine. For example, you could serve your HTML5 client at 123.45.678.9:80 (TCP), and serve your dedicated server at 123.45.678.9:7777 (UDP). You would run a web server and a dedicated ue4 server on the same machine.
Personally I would prefer to dedicate separate machines or containers to specific tasks, but it isn’t strictly necessary and just depends on your needs.