Q Light Controller+

How would I go about modifying the web interface? I am trying to create a web interface that ONLY has the currently loaded project's virtual console shown. No access to load projects, simple desk or configuration.

Use case:
I am creating an RGB matrix box as the base unit for a lighting setup for a 80's tribute rock band. The brains will be a Raspberry Pi, direct connected to a wireless router, that router will be plugged into a E1.31 to ASCN converter for 4 DMX universes, which plugs into 4 -100 count RGB pixels. When the Pi boots up, I am going to have QLC+ run as a service, with the web gui turned on. The GUI is auto launch a default sequence, and be ready for input. From a remote iPad (connected to the wireless router), the end user loads the webpage which points to QLC+ web interface. And they can run the various functions that we have given them access to.

This base unit would be able to accept E1.31 wireless connections from various elements on a stage. Light up mic stands, light up drum kits, guitar stands, fog machines.

I don't think you can. But you could just write your own HTML file that communicates with QLC's websocket.

Personally I would use a tablet with a OSC interface instead, like Touch OSC https://hexler.net/products/touchosc

Will QLC+ run OK as an app rather than a service on the PI? (I am not a PI user myself)

There are VNC clients for the iPad. You could connect to the PI this way and then run QLC+ in KIOSK mode.