Yes, with Episode 9 we're firmly past the halfway point of Act 1. As for Act 2 and 3 I'd say you're more or less correct on the relationship progression. I'm not sure when I'm going to handle pregnancies, but the procedure will likely be the same as it was in Sisterly Lust. Getting Jade or Ziv pregnant is an interesting question, some DNA-magic would indeed need to happen.
To answer your question about the harem @sycopter, Sisterly Lust has a harem path where you can romance Rachel, Bella, Liza, Susan, Adriana, Riley and Iris (or a different configuration) at once.