That will make a soft and snuggly blanket.
When mixing minky and flannel, you always want to pre-wash and shrink the flannel. Pearl cotton works well for tying minky. Yarn doesn't go through the minky as well. Usually, the tie is on the top. Or you could do the international stitch, where the tails are buried between the layers.
You might consider tacking it in spots with the sewing machine. Or even sewing a big square to hold the layers together.