Yes, you can download a BIOS update from a Mac.
Yes, you can download a BIOS update from a Mac.
Absolutely, all the work I've done only needs you to paste the files onto the root of a USB drive. It doesn't matter what operating system you use for that.
Use a flash drive that the system recognizes, such as FAT32 or similar. NTFS isn't supported on Macs by default.