To Potty Train or Not to Potty Train...

...That is the Mommy question of the week.
With the little timebomb inside me now set to detonate probably within a month, I have been scrambling in my OCD and list-maniac ways to get all the things that "need" to be done before baby arrives. Some of those things have been accomplished right on schedule, for example Adaya is reasonably settled into Chloe's room and I am slowly packing our "Honey, it's time" bag, as well as accumulating the necessities for baby: baby book, name letters for the wall, hand and footprint frames, peepee teepees and a puppy dog la-la (baby blankie like A and C have).
I figure some of the rest don't have to be done at least for another two weeks, including washing and organizing baby clothes and blankets, selling off most of our outgrown PINK clothes as well as outgrown maternity items and mentally giving myself a refresher course on all things natural during labor and birth. (eek!)
However, some things on that to-do list are not going as well as planned. For instance, the time is getting close to where I would like to have Chloe in the backseat of the minivan, so the baby car seat can be installed, but the transition is not going so well. Don't get me wrong, Chloe is VERY excited about this, but in order to move into the backseat, she needs to be able to strap herself in (check) and unbuckle herself as well (not check). She cannot seem to press the Graco button down hard enough to release the lower latches of her 5 point carseat and her frustration with that has led her to question if she can even undo the top latch, which only two weeks ago, she was handling like a pro.
But the biggest issue currently on my mind is that Adaya is not yet potty-trained. In fact, unlike Chloe, who was sitting on the potty at 18 months and had lots of peepee and poopoo action there even before she was fully trained at 27 months, Adaya has yet to "make" on the potty even ONCE in her 26 months. However, she is really interested in all things potty; always asking when mommy or Chloe goes, trying to "help" us with toilet paper and even asking to sit on the potty several times a day herself. Just for fun (and also in my true OCD fashion) I decided to run the numbers to see where Chloe was, relative to Adaya at this time and found out that if I was to follow the same potty timeline as Chloe (including Adaya's 5 day advance birthday), Adaya should be fully trained (daytime) by (gasp!) February 18th! That's only two weeks away!!!
Other than their completely different personalities, though, Adaya arrived 5 days before Chloe turned 2 so I knew I would never potty train Chloe before she became a big sister. However, Guppie is due when Adaya will be almost 28 months, so I've always wondered if I could potty train her before the baby comes and eliminate the need to wash DOUBLE the amount of cloth diapers for many more months. Of course, even if I could potty train her in the next month, won't she just regress after baby brother is here, anyway?
So, herein lies the dilemma: should I try to push her to be like her amazingly easy big sister and potty train her now, knowing that regression in a month is likely? Or should I wait for the dust to settle after her baby world is rocked with a litte brother and possibly miss the window of opportunity since she is so entralled with the potty right now?
Gah!