Since I have this phobia of having Error -50 pops up at me, I decided to encode them in 8 parts and re-essemble the 8 parts and encode the 8 parts into 1 file.
I don't understand this – splitting it into 8 parts, etc. If you're getting an Error-50, you may have problematic media. What are your original clips?
Q1) Unless you have an extremely complex project with loads of composited clips, effects and graphics, it's a pretty long export time. Maybe it has something to do with the eight parts?
Q2) To make different versions requires more time.