What a wonderful gift for your parents!!!
I have never been on Nordic but am considering it for next year so I have read a lot about her.
Nordic is not the oldest RCCL ship, but it is the smallest in the fleet. I hear the crew and service is excellent!
I do not think you will find safes in the cabins, your parents will need to secure valuables in a safe with the purser if that is what they need. The older ships like Nordic and Sovereign do not have safes in he cabins.
8th deck cabin? Did you get to see the deck plans if you booked through an agent? The deck plans usually have the fine print about whether your cabin's oceanview view is partially obstructed.
If you go to
http://leisure.travelocity.com/Vacat...ITY_87,00.html
you can see a lot of info about the ship and take a look at the deck plans. Expect that he cabin will be VERY small. But little time is usually spent in cabin, so it should not be too big of an issue.
Deck 8:
http://leisure.travelocity.com/Vacat...7_543_,00.html
The gratuities that you pre-paid will cover:
Assistant waiter
Waiter
Cabin steward
Your parents "should" receive vouchers to put in the tipping envelopes that will arrive at their stateroom the day before the cruise ends. The tipping envelopes then can be given to the Assistant waiter and Waiter at dinner that last night. They can give the envelope for the Cabin steward directly or leave it in an obvious place in the cabin. The Head Waiter is only tipped if he performs a service for you, so it is not covered in pre-paid (as far as I have been told).
Gratuities are added to cocktail orders automatically.
As for excursion recommendations, do your parents know you have done this for them? When the travel documents arrive, they can read the descriptions and decide what interests them. The excursions can be booked online, so they can tell you and you can book for them if you wish.
I'm sure this will be a very enjoyable trip for your parents. My sister and I took our Mom on a cruise for Christmas and she is 62 and had a blast!
I hope some of my answers help you.
Dana