Something else too with trying too hard to buy lifetime status:
The cost to get it according to OP's plan is 100000+ NOK. It's a lot of money if you are only doing MR. You can buy a lot of lounge access and extra bags. I haven't got much luck getting upgraded as *G.
You will need more than 1 *G to get lounge access if you have a family. You might be able to get away when you only have one small child. Right now SAS gives access to families in their own lounge so you are covered as long as you are using their lounges.
As for Mariott, we haven't been a member (7 years) long enough to have the points and nights to become lifetime status members (we could have been if we poured money into buying nights and points). We chose not to because it's a lot of money for maybe something. We will see what happens with the next devaluation. I'm considering using the points for travel packages.