Personally I’d say you’re approach is sound - disable any services that you don’t need to keep things lean and simple. In addition to your DLNA and iTunes, also you may want to include cloud support for the WD apps as well. If you turn that off then you cut down on the cataloguing and indexing that the MCM needs to do, and you’ll also cut out all the “hidden” .wdmc folders that get created where the MCM stores the information from that indexing (otherwise you’ll get one per folder that has indexed files in it).
The key point is to make your decision on which features you want enabled/disabled, and how you want the drives themselves set up (RAID0, RAID1, JBOD or spanning) before you start moving any data onto the MCM.
As for the firmwares, it depends a little what firmware your MCM arrives with. I’d review the release notes for any subsequent firmware and then make an informed decision as to whether those features/fixes are worth the update or not. On my MCM the current firmware (1.05.30) works fine, and the updating is easy via the dashboard.
If I were you though, I’d use JBOD (“Just a Bunch of Disks”, basically using each drive independently) rather than RAID0. Whilst it has the disadvantage that you can fill one drive before the other (and you can’t see from the dashboard how full each drive individually actually is, you only get a total free space available count although mapping drives and looking at the used/free space reported there can overcome that), it does have the distinct advantage that if you lose one drive then the other is totally unaffected, whereas in RAID0 (and in spanning) mode if you lose one then you may well lose much more of your data as it will be randomly distributed across both drives. You will of course lose the “mirror copy” protection of RAID1, but you’ll double your available capacity.
There are ways to do external drive back-up via the dashboard, but I must admit I’ve never actually tried it so I can’t tell you if they work, or how well they do. Have a look in the MCM user manual though, as that is quite detailed in what options are available from the dashboard for backing up and file transfer.