The original intent of the series was that would tell stories that could build upon ideas presented in earlier works. As time went on and with more games, things started to get overwhelming for newcomers which is why the classifications of: Canon, stand-alone, non-canon were devised to attempt to sort things out into something more manageable. At end of the day, if you've got a story idea go for it. If you questions about characters, locations or the series history, don't hesitate to create a forum post and ask.
Re: Jackie working at Dominatrix, she didn't until both you and DarkWater decided she did... in two separate games without talking to each other about it, I'd wager. Also, it's easy to claim that Nick had sprained wrists & couldn't play drums in "Rock" which is why Chris played them (rationalizations are fun
Back to the topic on hand, yay more content, downloading now.