I see the main difference, besides the price, between the MLD tarps is that the Solo Pro Cuben is a lot less wide than the Cuben Grace tarps. This is to cut the cost considerably by using only the width of one roll of cuben fiber. I am sure its an awesome tarp, brand new. With the superlite bivy you will be very happy, and it is the lightest and cheapest piece you have listed. Assuming you have tarped before, correct?
In terms of a quilt I would suggest making your own. It will be a great project, much cheaper, and likely lighter than what you listed. Kits can be found at Thru-hiker.
Not sure if you already knew any of this. If you did, please disregard this post! Anyway, good luck!