How can I reconstruct my Grandmother's recipe from just ingredients?
I think that actually you already have all the information you need. Let's go through the questions you mention:

You can use whichever process you prefer. Any of the usual methods for making yeast dough will give you the same result here.

This is the wrong question to ask. Deciding on the baking time first and choosing the thickness second is very difficult and serves no purpose. Just use the thickness you prefer and then bake until done, no matter how long it takes. Obviously, don't go with anything crazy the first time, use a thickness that is somewhere within the typical roll range, accounting for rising.

Yes, this kind of buns is generally arranged with sides touching before rising.

I think that it is intentional to use the sauce before baking, but you can try both ways and see which you like more. Both will produce edible rolls, and if you distrust your grandfather's memory, there is only one way to discover which one was your grandmother's preferred method - a side-by-side test.


So good luck, and go enjoy some nice rolls.