Thank Joe! Helped confirm some things I knew, but didn’t have the reference! 
Would H Clips be necessary if the roofing material on the sheathing is metal shingle?
Welcome Rhonda! A lot of discussion for when, why and where H Clips are used. It appears that the best plausible answer is that these clips help with continual weight support at the butts and seams for the roof sheathing. Are they required are not for the type of roof cover may depend on the covering manufacture’s recommendations or local codes.
Yes under certain conditions. A pic of the OSB manufacturer’s stamp would have been helpful.