If you are not using any LVM, and are not using any “btrfs” then it is probably safe to mask or disable those two. Note, however, that if you plug in an external drive that uses “btrfs” or “lvm” then you might need them at that time.
In my case, I use a disk encryption which is using an encrypted LVM. So I need those.
As for “postfix” - it is probably used for system generated email (messages about errors sent to root by the system).