@ Jay, check your slave cylinder for deffinate, you may well have a slight leak by the sounds of things!
But for CERTAIN, the problem with your clutch pedal not returning-is the lack of a clutch return spring lol!! I had the exact same problem, even after changing the s/cylinder. Cost about 2.40 from Fiat and is a bugger to fit inverted and in the dark! Quiet an odd shape sp[ring and very stiff, so one from an unused eck-chair will not suffice! It will fix the return problem in a jiffy, but at first will make the clutch a little stiffer and more 'springy' funnily enough!
I never noticed mine snap, no ping or anything, but now its as good as new.