On the Peppa Pig reward: as a general rule, that kind of delayed-gratification reward doesn't really work well for young kids; they don't yet have the reasoning skills to understand delayed gratification. They will do the desired behaviour once and then when the promised reward doesn't appear, they usually abandon the effort (or get angry and deliberately sabotage it, even if unconsciously.) If you really feel you have to do that kind of future reward, the way to do it is to tie little immediate rewards to it, such as making her a sticker chart, then giving her a fancy sticker to fill in the box every time she demonstrates the desired behaviour. When all the boxes are filled in, then she gets the big reward. (Show tickets are usually not a great idea for this because they have to be purchased in advance. I'd go more for something like a trip to the zoo or a special trip with Mommy to get their hair done, that can easily be scheduled or canceled at will.) That way she does get a reward right away and feels much more like doing what you want is actually worth something.
As a previous poster noted, kids almost always regress when a new sibling is born, so while I agree it's best to try to toilet-train her before the new baby arrives, go easy on the "big girl" part of the praise. Once the baby is born and starts getting all the attention, she's going to see really quickly that being the "big girl" is actually not a good deal, and will almost surely try to become a "baby" again, because the baby seems better off. It's probably better to emphasize the icky part of nappies, like being stinky or itchy, or having a heavy nappy impeding how fast she can run, or having to spend so much time away from play getting it changed, when going to the toilet on her own is very quick and doesn't require an adult's help. Also, if at all possible, have Daddy spend a lot of special alone time with her now and going forward; to lessen the hurt of losing so much of Mum's attention.
Be sure to set up your toilet with nice-smelling "special" hand-soap and a step stool so that she can use it on her own. We got a small toilet ring that fit between the regular one and the toilet lid, and left it in the down position when the toilet wasn't in use. (The adults can simply flip it up out of the way. Our kids had that on the toilet here until about age 6, as it was more comfortable not having to balance on the rim.) Kids differ on whether or not they are frightened of being sucked into a toilet; if she is, use the kind that you have to empty for awhile.
Best of luck. FWIW, both of ours also were stubborn about toileting and held out as long as possible, but the threat of being left behind and not getting to go to preschool (Reception, in UK terms) with all their nursery friends finally did the trick.
PS: Funny story for you: our eldest was a definite pacifier junkie from birth, but when he was baptized at age 4 months his godmother accidentally dropped it into the font of Holy Water during the ceremony. When she retrieved it and handed it back to him, he immediately spit it out and refused to use one ever after that. I don't know if it was divine intervention, or an early indicator that he would grow up to be an atheist, but it was incredibly funny. (He did grow up to be an athiest, BTW. Hated parochial school just that much.)
The pacifier fairy is the one I see the most - put all the pacifiers in an envelope and leave them outside for the fairy. She'll take them to other babies and leave a toy.
