Cream cheese or butter, for example

No. There are two kinds of Puck cream: the spread and the canned cream. The spread is like soft cream cheese, and the canned cream is almost solid, like the consistency of pudding. It's unique and not the same as either double cream, or heavy cream. It is quite popular in Saudi Arabia.

Yes, Amul cheese spread can be substituted for cream cheese, but beware it has a higher salt content. Other substitutions include blended cottage cheese and plain yogurt.

Make one cake and slice it in half and either spread the butter cream over it and sandwitch them together.

Or, make two halves of a cake and spread the butter cream over it and sandwitch them together.

Yes. They main difference between cream cheese spread and cream cheese is that the spread may have been aerated, to enhance spreadability. This makes no difference when you're following a recipe with weight-based measurements (since air weighs very little), but if you're following a recipe with volume-based measurements (e.g cups), you should compact the cream cheese spread as much as possible.