It all depends on taste [of course].
Lower fat milk & yoghurt are sharper, more tangy, almost 'lemony'.
High fat are rich, smooth & creamy.
So, start with 'How tart do you like your lassi?' & work from there.
Personally, I like lassi to have some 'bite' to it, so I'd go for zero-fat yoghurt & probably what in the UK would be called semi-...
Saturation doesn't effect the extraction or distribution of flavors, your beef stew was just more flavorful than your chicken stew. Any fat (and that includes oil) will do the job, the difference is in the flavor of the fat and texture differences you would get from the different oils. Beef fat will be richer than olive oil, giving the impression of flavor ...
You could use butter, of course, which would make it delicious like everything made with butter is. But duck fat has a higher melting point than butter and in that respect is more like lard. Duck fat is super delicious. Also it seems to me duck fat is more in accord with the overall ethos of a game meat pie.
You could buy plain duck fat. Or ...
Shortbread dough made with lard is delicious. I have never used beef fat, but both pork fat and goose fat have worked perfectly for me in this setting. I prefer the texture over the texture of shortbread baked with butter. So go ahead and make it, it's very likely that you get very similar results to pork or goose fat.
Firstly, I would challenge both of your assumptions.
(a) dripping doesn't go off
Like any other fat, lamb drippings can and will go rancid over time.
(b) any germs/bacteria would be killed by the heat of frying
While it's true that any molds or bacteria themselves will be killed by heat, the same does not hold for any toxins they may have produced.
First, a little chemistry primer on what unsaturated fatty acids look like (this is petroselinic acid):
By Yikrazuul (talk) - Own work, Public domain, Link
You can see the double bond near the "middle" of the molecule. The "rest" of the molecule is attached to the same side of the double bond axis on both ends, making this a "cis" fatty acid. Rotation ...
That's a piece of the rind of the bacon, which is yellow because it was exposed to the smoke. The bacon shifted while being sliced, causing the strip to end up attached to that one piece rather than in bits on the others. It's fine to eat.
The problem here is that it doesn't work as you suggest,
the fat keeps the leaner game meats from drying out
What you have in your recipe is not fat, it's bacon and belly, which is fat-rich tissue. When baking, the lean meat still dries out, the bacon stays soft, and the combination feels much juicier than the pure lean meat. If you simply add some ...
Fat helps carry flavor, it also add to the mouth-feel of the final product. Fat also adds flavor. So, getting the "flavor into the fat", or probably better put, to be carried by the fat, is only part of the equation. So, in part this depends on why the fat is necessary for a particular dish. There are all types of curries, so clarifying your recipe and ...