Nope, for mbr even a NTFS formatted usb works. I only format the USB fat32 in explorer and extract the iso to it, for 8.1/10 it works for UEFI and Legacy BIOS, for 7 also only not on non CSM systems.
At first I thought transparency wasn't working for me too but look closer, it's not just transparency anymore, it's now called acrylic, softer than I would like it to be.
I had a bug with my clean install in that the search box was white! It stuck out like a sore thumb on my dark theme Fortunately the old trick of changing country/region and back again fixed it.
The sentence in bold got me laughing. Why would you want to do that? However, I agree with you the 'fluent design' of the notification and action centre would tempt anybody who is not an Insider to install the Build. Expect to come across many bugs which will irritate you along the way. So it is advisable not to run it on your cherished 'production' laptop because it is a test Build.
LOL, I do not own a laptop, and have only one computer. I run it as my cherished production computer for proper testing.