1. You can right click the choice you want to make and open it in a new window or tab. That should be no surprise to anyone who plays online games like this. However, when you do so, your effect (positive or negative "inf", etc) is stored and will be immediately applied to your next choice (EVEN IF the next choice is in a different window/tab). You can then close that tab and do it over and over for infinite "inf" and relationship increases and the only thing that goes wrong is the clock eventually stops working and shows "error". Also, if you EVER ask for the blowjob or anything that is "negative", that effect also stays with you forever. So, if you want the "perfect" game, do not ask for the blowjob thinking you can just carry on in a different tab/window because the effect is that Bridgette still tells the principal and this spoils conversations with other people (Didi in the hall).
2. Having done this, I ended with every person in the game completely in love with me and "inf" maxed out. This gave me the same code as mentioned earlier (A769#). So, I assume this to be the "best" code.
3. During those build actions, I have found that: A) yes you can have complete sex with Maria (but you get caught and fired) in addition to getting a blowjob under the desk (which is very likely to get you caught and fired). B) Yes, the girls WILL follow you back to your office and start to strip. But, you guessed it, you get caught and fired.