1) yes, correct
2) if you didnt choose anything else, you probably already have an SHR volume with no disk redundancy. But even if not, it doesnt matter, if you expand it with additional disks, it will be converted anyway without data loss.
3) not really. You could add a smaller HD and create a new volume with it instead of expanding the old one. Then move data from old to new volume, delete old volume and add the old disk to the new volume.
*Please do not Private Message me for support questions; leave it on the forum so all members can learn. Thanks!*
DS712+ / DSM 4.2 3211 / 2 x HD204UI (RAID0) / LMS 7.7.2-007
DS110+ / DSM 4.2 3211 / HD154UI
DS408 / DSM 4.0 2228 / 3 x ST31000340AS (RAID0) + 1 x HDS721010KLA330
DS207+ / DSM 3.1.1636 / ST31000340AS + WD5000KS
DS-106x / DSM 4.0 2228 (from DS108j) /
2 Squeezebox 3 + Boom
APC Smart UPS SUA750i