No one is really able to get the P3 to do what was promised, establish wireless connection through a bridge
This is not correct, many users are using a wireless bridge, of course only the issues are reported in forums.

The problem is: We don't know every wireless hardware from other manufacturers and how to use it - so it is not easy to give here much assistance. You are writing "WORKING device" - but what does this mean? When I plug in a new electronic device it is also working in some way - but it must be setup to work CORRECTLY.

Ok, let's try this.
First you should establish a simple DIRECT WIRED connection without a wireless bridge between. Set 192.168.2.xxx for ProfiLux (must be unique address don't forget to reboot).
Connect with ProfiLuxControl 192.168.2.xxx and with webbrowser. If successfull we should move to the next step.