Re: transitioning from ec to pt?
Honestly, I think some of it is developmental. I part time EC'ed with my DD. We would go to the potty upon waking, before and after naps, before tub, and before bed. She didn't show a true interest in holding it for the potty until 24-26 months. She will be 3 next month and is still not night trained (wears a pull up and wets 1-2 weekly).
I think if you just encourage regular potty trips and keep up the communication (the signing, the rewards), she will get it eventually. For us, stickers were a huge reward. We started a sticker book and DS loved to collect 1 sticker after each pee and 2 stickers for each poop.