Can I alter the swag?
We cannot give you instructions to alter the swag in width or depth. To go beyond the sizes given would require the shape and size of the pattern, and the pleat angles to change. There is no formula for a quick fix.

I would like to interline these with a soft flannel. Would teardrops still fold gracefully? Also, has this particular pattern been sewn without the tails? I am contemplating omitting them.
Interlining is a wonderful addition to the swag. Yes, the valance is also beautiful without the tails.

I have pattern 9260 and I was wondering if the drapery swag I swag section MUST be cut on the bias. I am dealing with an upright design in the fabric.
It will hang better on the bias, but if you must cut upright, cut the lining on the bias. This will help.