There is certainly nothing wrong with gelling. I prefer the coloring of it myself. Anyway, the cracking means that it began to overheat. If you have your mold insulated and it begins to overheat, usually it just takes uncovering it. If you didn't have it covered or insulated, then you can move it to a cooler room, put it in the fridge or the freezer.
Certainly some eo's and fo's heat more than others, just like some accelerate trace. It doesn't make them unusable, it just means that you have to be a little more cautious when using them. Speaking of which, I hope that you are being careful and double checking the usage rates of your scents (eo's/fo's).
Not sure about how much vanilla you used, but it will probably change the color of your soap, at least to some degree. So make sure to take pictures of this soap every week so that you can see what amount of vanilla does what. It is pretty interesting.
Your soap looks great, congrats and welcome to the addiction!