Hi and congratulations for your first reader.
2) It's probably a problem the way your program renders PDFs, which are BTW the worst format for ereaders
3) Settings -> appearance, but the pictures are only shown in four shades of grey, you can also set the last read page for startup, so can start reading during boot process
4) This setting is only for the fbreader, unfortunately no chance for the other ones. With fbreader180 or coolreader 3 you can switch it off permanent.
5) Sorry, no clue
Have fun reading...