#1 – I have seen this before on a few notes and this would not consider this an error. Why? Unfortunately your notes and the ones I have seen have been circulated. Anything can happen in circulation, soaked in oil, washed in the wash, etc. It is scary to think what might really be on the note.
#2 – I have also seen these small ink marks on top and the bottom of notes before, and these are very minor. The bird series near the end seamed to be very sloppy, and had similar ink marks on them. I guess you could consider this a very very minor error, and I am not sure you would get a huge premium is any over face value.
It is important to remember this is a hobby, and if you like the notes, hang on to them and enjoy them.
Great questions, and welcome to the forum.