Verification is optional, but recommended. This is true for all OSs. Don't do it if you can't.

Note that I said to buy a USB or DVD with Linux. Burning your own is easy on Linux, but Windows puts up a lot of roadblocks. (One wonders why.)

GRUB works fine, but again, you only have to deal with it if you want to dual-boot.

Some sound cards used to not have first-party Linux drivers, so you'd have to find some third-party workaround. This is the only real problem among the ones you listed, but even this is pretty rare nowadays.