Here in Manitoba, lots of mukluks, slippers, mittens are handmade from deer skin.. Lots of deer population, and cattle in this area.. What I know it requires special needle, and I wonder about the ironing of your seams part. The cleaning is via use of sandpaper.. Not in machine..
The skin punctures and leaves hole, that could tear... I'd talk to a leather shop that does leather crafts before taking on this task.. All the work you put into it want the quilt to last.