It depends:
Majority of studies have shown that saturated fat increases LDL cholesterol and causes cardiovascular diseases, though in some of them saturated fat doesn’t cause these problems.
So this topic about saturated fat is unclear, it is better to consume it in little amount to be safe
Unprocessed dairy (I.e. heavy cream) is better than processed dairy like butter. I cant find the link but its an increase vs No increase in something. I’m sure a google scholar search will bring it up. Something like “heavy cream vs butter study”.
From what I know about r/keto, yes.
0 carbs means no added sugar. If you are making whipped cream and you want it sweet you could add a sugar substitute. I add a little vanilla and monk fruit/erythritol sweetener, and then whip.