If delivered (many online orders like this get screwed up) few, if any, of these types of gifts are worth the money. Unlikely he'll see the order. If you really want to treat him to something, buy a specialty lunch at a heavy discount (that probably has more value that the gift you envisioned) with the current Black Friday sale.
Depends on when you booked - for any recent bookings you lose the entire deposit if you cancel. The $100 penalty only applies if you move to another sailing.
When you click on the MDR a menu option should come up. If not, it may not be available for your sailing yet, you'll have to set the app to a closer in sailing. Also, you can buy now (I assume due to a sale) for some night and then move it once on board.
But, with most folks on a cruise watching it on a mobile device, you can get pretty good video at about 1-2Mbps. That's why the usual 4Mbps throttling of Voom is fine most use cases.
Yes, CEO Liberty mentioned that's the new way they will manage inventory. The mantra of "always book early for best prices" may be even less true going forward.