nothing you can do, youtube compressing the video and lowers quality, from my understanding you have to be partnered etc etc to get best video quality they optimize for speed, not quality.
https://support.google.com/youtube/answer/1722171?hl=en
$200 for all 3? you will get okay products but don't expect them to be great for that budget. as wireless headphones are on the pricey side
$198 if you do some price shopping can be cheaper
http://gaming.logitech.com/en-us/product/g230-stereo-gaming-headset...
when you plug the headset in is your speakers still plugged in aswell? go to your speaker icon, right click playback devices, find your headset and set it has default device, then disable your speakers, does that work?
http://www.xoticpc.com/sager-np8677s-clevo-p670re-p-8653.html?startcustomization=1
abit cheaper it seems. I personally can vouch for sager, my old one was very nice but i upgraded to a desktop and sold it. and as far as lower quality thats entirely up to you, but getting a quality gaming laptop...
I wouldn't have any idea why you have echos, but everyone i know that owns senheiser products claim that are amazing.
Hope you get it figured out and get into the comp level.
~Global Elite