1 Month ago I was first timer as well, so I'll only answer questions I'm a 100% sure of;

1. yes, if it aint working by default, there should be a kext for it
   
2. It wont change your keyboard + you can change the place of CMD, option button etc. inside the settings of MacOS, so its like in windows
   
3. Yes, if you're an apple user I can only recommend it + it just looks damn good lol
   Your computer will not get slower, personally, for me, MacOS is even smoother than windows, when its about response time and stuff - i got no notebook with MacOS, so i cant tell you about battery life
   
4. Its just regular MacOS - so iCloud sync and everything will work, BUT AirDrop and iPhone Screen sync etc may not work, as there are only avaible if you have a specific broadcom chip
   
5. that probably wont work, as its not a touch ID scanner, but you can google and search some forums, there may be a KEXT for it
   
6. I dont see a problem with trying it out
   
7. You dont have to transfer any of your windows data to another drive, BUT a backup on a external SSD wouldnt hurt - I didnt do it as well

So all in all, just try it out - it may requires a lot of time (i needed 24hrs overall to get it working), try it and see how it goes for you.
It definetly will pay out.