Questions about foie gras

So the MIL has asked for some foie gras for Christmas. I know plenty of places to get it, but I don't know what to get. I figure she doesn't want straight foie gras that she has to vein and prep herself. So then it's either terrine or mousse, right? I was planning to get this from Hudson Valley Foie Gras along with some duck fat and other goodies. But I'm a little uncertain what to get. My wife votes for two pounds of terrine, plus some mousse, fat, and duck salami. My question, is that while the 2lb terrine's unit cost is WAY lower than the smaller size, what do you do with 2lb of terrine? Can you store some of it so it lasts longer? How long and what's the method? Would it be better to get some foie gras medallions from d'Artagnan? Are those easier to store long term?

Sorry for the dumb questions, but this is something I don't cook with, well, ever.

if you have a vacuum sealer, you can cut it into portions and place it in the freezer and thaw out as you need it. most of it is fat, so it will freeze well. You should be able to get at least 6 months out of it this way. It being the christmas season, throw a party and it will be gone pretty damn quick.

2lbs is really only 12 portions at 3 oz each. No problem serving that up at a party. What I do is melt the duck fat down and pour it over the terrine to seal it when it chills. Now when you need some simply slice off the portion you need and use a piece off the end as sort of an end cap. Melt the fat you removed from the portion you are serving to re seal. It always stays sealed and ready to use.

Sounds like a very nice, intuitive system.

Uh oh. Appears like I might be a bit slow on this one. So I've got my terrine. It's all nice and setup in it's loaf-pan-shaped mold. In the above system, I would:
a.) slice a portion from middle of the terrine in the mold. Remove that portion. Push the now two halves of the terrine left in the mold together, and re-seal with fat, including the now vacant space at the end of the mold.
b.) extract the terrine from the mold, take a length-wise slice from the terrine (not a "slice" from the loaf, but rather as if I were removing the top crust from a loaf). Put remaining back in mold and reseal with fat.
c.) Something else altogether that I didn't get cuz as I'm super-duper slow...

a.) Seems logical, but I'd end up going through a crazy amount of duck fat as I get to the end of the terrine, no?
b.) Seems logical, but I'd be heating and cooling the terrine a lot to get it in and out of it's mold, or?

1. Melt fat only till aqueous(not ripping hot) and pour over entire terrine.
2. Wait till completely chilled and hardened.
3. Slice off portion to be served and simply brush off the fat from that portion and melt till aqueous.
4. From that portion slice off 1/4" end cap.
5. Place end cap back in terrine and re seal with the melted fat from the served portion.
6. Anytime you want to serve simply remove end cap, slice new portion out and remove and reseal with the end cap.

Also just leave the whole thing in the terrine the whole time and only take out what's needed.

Got it. The end-cap bit confused me at first, but I get it now. sounds like a good system. Thanks for the advice and patience!