Leave the burlap there and just wait for it to decompose; you could also put down a 1/2" layer of Miracle-Gro soil on top of the burlap to cover it which will help hide the burlap while providing a more enriching soil for the grass to grow in.
This product is being used to wrap young bushes and other plants from winter winds. As for the purpose of your question please consult either the label of manufacturer.
If you are protecting shrubs by wrapping, or creating a "snow fence", you want the permeability of the burlap. It needs to breathe. Even snow fences are permeable slats or plastic grids. BobA
Yes it would work
Nope,,,It must be taken up when seed germinates. Burlap protects seeds from birds and other seed loving critters but the weave on it will hinder growth after seeds have sprouted.
I don't think it is meant for that purpose. Weed barriers do not let light or water in. Burlap is an open mesh type fabric.
No, none of those ingredients
This would work
I planted new grass seed, staked the burlap over the area to protect seeds from birds and dogs and watered for 3 weeks. The grass poked through the loose weave so I pulled the metal staples out took up the burlap and washed it in a sudsy pail and hung to dry. I will use it again when needed. Not sure about how long to break down if left outside.