you ever thought of just having a 1 ssid from the dsl connection and bypass all of your other stuff, clearly if your having nat rules then id happily point towards your setup and chances are its some sort of firewall rule internal thats your issue rather than anything else. your xbox actually uses teredo tunneling and im not entirely sure of what the ps4 uses i tend to have mine as a dust collector so im not the best with their protocols,
or alternatively you could get the free software on your laptop and broadcast an SSID with that and allow the switch to connect to it.
this software is decent http://www.mypublicwifi.com/publicwifi/en/index.html its free and does the job, also if you really wanted you could share the interface on your laptop with the one this software makes to share the network traffic so your hotspot would essentially be your vpn traffic.
i havn't read your entire post upon typing this but i refer quickly to it, if you have to make a new vlan then you clearly have firewall rules not setup correctly.
You can do it without any external hardware.
I've made my laptop a wifi hot spot using MyPublicWifi and then connect your controller to that.
That means you don't need any internet for it to work.
What are you using, phone, tablet, ipad..?
You say you have been using touch osc, how was it working already?
The software I use is called mypublic wifi, link is here http://www.mypublicwifi.com/publicwifi/en/index.html
I currently use it in my dorm to create a wireless signal from my ethernet cable, but I think the same idea should I apply to extending a wifi signal. It may not be strong enough for fast online gaming, but might be enough for just updating your wii u and keeping it connected. Good luck!
I'm still kind of new to plex, but this sounds similar to something I've done a bit of. if the laptop is a windows laptop use a program like Connectify or MyPublicWifi to create a WiFi hotspot directly from your laptop, no other hardware should be required. Connectify is a paid program but has a trial that should do what you're after.
You could give this a try: http://www.mypublicwifi.com/publicwifi/en/index.html
It's listed to be compatible with windows xp on some pages at least.
What you probably want to look for is on how to utilize your laptop as a wifi repeater on windows xp.
You can try Virtual Wifi Router or MyPublicWifi which acts as reverse tethering; allows you to create a local wireless network from your laptop, and your friends can connect to that via wifi.
Here are some more if you don't like the two examples/they don't work for you.
You could try going into your router via your computer (do ipconfig in a cmd windows to find the ip of your router, sometimes its even written on the router itself) and then change the settings from there. If it asks you for a password, its sometimes written on the router itself. Alternatively you could get a program called (MyPublicWifi)[http://www.mypublicwifi.com/publicwifi/en/index.html] and setup your computer to BE a hotspot for your DS.
If you have an inbuilt wifi card on your PC, the easiest way is to use a program called 'MyPublicWifi'.
iDevice to PC > connection to MyPublicWifi > wifi to other devices
EDIT - To do this, you must share your iDevices connection via USB. Wifi cards can seem to only handle one connection so you can't connect via wifi and share via wifi from a PC at the same time.