[CentOS] EFI and RAID questions

Hi All;

I have a new server we're setting up that supports EFI or Legacy in the bios

I am a solid database guy but my SA skills are limited to what I need to 
get by

1) I used EFI because I wanted to create a raid 10 array with 6 4TB 
drives and apparently I cannot setup gpt partitions via parted in legacy 
mode (at least that's what I've read - is this true?)

2) I installed the OS on 2 500GB drives, I used to do all my installs 
with software RAID (mirrored) without LVM as follows:
- create 2 raid partitions (one on each drive)  for swap, /boot and /
- create a raid1 device for each set of partitions above

The installer would not let me proceed without a /boot/efi partition I 
tried to create a raid partition on each drive for this and create a 
/boot/efi raid disk but when I doit this way in the installer I no 
longer see the "EFI SYSTEM Partition" as an option for the filesystem 
type so this did not work either.

I ended up doing hardware raid for the OS drives and software raid for 
the 6 4TB data drives. It works but I prefer to do software raid for 
everything so we ca have standard methods of monitoring for bad drives.

Is there a way to setup software raid with EFI?

Do I need to add a /boot/efi partition only to one of the 2 OS drives?
If so how do I recover if we loose the drive with the /boot/efi partition?

Is it required to use LVM to do this?

Thanks in advance