1. What is the uncertainty about with dating these fragments? I know in dating Greek mss paleontologists can usually get to within 50 years, plus or minus. Are the Coptic scholars comparing these to other dated mss?

The mss are datable once found. There is only one scholar working on this. The issue is dating the contents and finding the mss. Right now all that exists are photographs. The collection they were a part of was huge; the fragments are small. 

2. What were these Coptic fragments doing since the 1970s such that nobody read them to determine their contents? How many other mss, Greek/Latin/Syriac/Coptic/etc. are there that have been discovered but still have not yet been read to determine their contents? At least someone should photograph these and post them on a website so scholars can look at them to see if there are any old, important NT mss!

They are a part of a collection of thousands of pieces of material that are only now being analyzed. These pieces are not easy to locate or photograph and then read. It is a slow process.