The vapor barrier is mainly to keep the insulation dry. If you have any potential water problems, seal the block first. I would recommend sealing the block with a block sealer containing portland cement. This helps insure that problems don't occur later. But, since you already put up the framing, sealing the block will be more difficult.
Remember that water vapor is a gas, and can pass through cement walls that don't leak water (a liquid). Condensation can also lead to moisture.
The kraft paper is not a vapor barrier. I don't know about sealing at the top.
Just remember that basements can at times get wet like when the hot water tank decides to burst. You might consider using foam insulation that is also waterproof.
Read through the older posts & you should see many others have asked the same question. You can search use your "Edit -- Find in Page" feature and search with a keyword like "basement"