Welcome to LMCE. I'm a newbie too but I'm hoping that my experiences can help you make some of the right decisions.
You'll need to do more research than you have done so far. Many of the questions that you asked are already answered multiple times in these forums and on the Wiki. I'm not hating, I'm just trying to give you a friendly warning that some/many of the bigger LMCE supporters get frustrated when people ask questions that they have answered many, many times. Trust me, I made and continue to make the mistake of asking questions that I could have or can answer on my own.
Again, I'm a newbie so don't take anything that I say as gospel but hopefully it will be a starting point. Here are some of the things that I see which may be problems:
Blu Ray - There is no reason to have a blu ray on the core and blu ray doesn't play nice with Linux
Orbiter - What are you planning on using as an orbiter?
Laptops - How do you plan on using the windows laptops? I don't believe that PXE works with wireless (well or at all)
HDTV Tuner - I'm not familiar with UK TV. Are you planning on OTA or over cable? If cable is the signal unencrypted?
If you are like me then you will want to try to get every piece at the lowest possible cost. Unfortunately the money spent on the equipment was the least significant cost in me getting my LMCE box running (I'm still trying to get all the features working). The time spent on getting non-compatible (or not commonly used) pieces working has been the most significant cost. I highly recommend that you consider buying a core from some place like http://lmcecompatible.com/
. I bought a barebones core from them and it was the best decision I made. I seem to have had troubles with the pieces that I found "good deals" on and bought elsewhere.
I hope that this helps a bit.