Hello,
It sounds like you have alot of wonderful fabrics that somone loved!
You can use any evenweave fabric with Cross Stitch on the machine.
Your stitching will look most realistic, if you can match the count of the design to the count of the fabric. For example, stitch a 14 Count design on 14 Count Aida Cloth or 28 Count Linen Evenweave fabrics. Try to hoop the fabric as straight in your hoop as possible, then position the needle to go down into a corner of an aida square or cleanly into the evenweave fabric between threads.
You can also stitch quite well on a smaller count cross stitch fabric, even thought the stitches will be smaller than a single square. The results aren't quite "perfect" as far as stitching matching the fabric, but the overall look should be very nice. The Cross Stitch fabrics come in such wonderful colors and are nice, stable fabrics for machine embroidery as well!
I hope you'll try this...you'll like the results, I'm sure!
Donna