Hey John! I am your friendly neighborhood Farscape fanatic, and I will be glad to answer all of your questions.
1. Sadly the show has been canceled, but there's a tremendously huge campaign to bring back the series and I think we've got a solid chance. Especially since the Henson company was recently bought back by Jim Henson's children, and the family is highly committed to the show.
2. The Peacekeepers start out as the main villain group on the show, but the focus on them shifts somewhat slightly throughout the series. They hint in Season Four as if they're going to explain the link between humans, Sebaceans (Peacekeepers' proper name), and one other species that all look very similar. Unfortunately they never had the chance to explore that further before the cancellation.
3. Everyone speaks english because pretty much everyone in the known universe is implanted with translator microbes upon birth, so that all species can communicate freely with one another. Unfortunately, one of the earliest (and in my opinion, the absolute worst) episodes completely ignores that concept and has a bunch of aliens who couldn't have possibly gotten microbes speaking in english.
4. There are PLENTY of great characters who come in and join the cast along the way, more than a few of them being hot chicks. Chiana is the absolute best one, and she comes in at Episode 15 in the first season. She's the purdiest alien girl ever
I know I said before that I'd make you some copies of the series so you could check it out and see if you liked it. I can still do that if you want. It's my favorite TV series of all time, and I'll argue with anyone here that it's the best science fiction TV show ever made.