Also, do I have to pay monthly to unlock the plus version content or can I make a one time payment to get the extra scenes lol?
To your first question; Caine will be getting a release very soon! It will happen in the upcoming weeks, stay tuned for an actual release date.
To your second question; no, you do not have to pledge every month. You can pledge once, get the goods, and cancel your pledge if you like :) Staying on a monthly basis means you'll get an updated game and access to more content for the current character in development (James at the moment).
Thank you! Also, if I buy the stuff now (as in before Jame's route is released) as a one time pledge, will I have to purchase again to get the extra scenes of the next character (James)?
Pledging every month means getting new updates. James is currently in development, with roughly 2 chapters released every month. If you stop pledging, you're not privy to any future content, so you do not get James' latest chapters.
So if you pledged and have access to James' chapters 1 through 10, then that's all you'll get. People stay pledged so they can get the update every month :)