program free download-- http://www.tamasoft.co.jp/pepakura-en/
time depends... but for your first time probly a week or two also depending on how much time u spend on it
The Exacto knife works soooo much better. However you will need a cutting surface. This is because the knife is much more maneuverable, accurate, and fast than scissors.
Btw, I dont know what you need a black and red pen for.