Aww, I am totally smitten with our baby too. She is 4.5 months and ~13 lbs.
Sorry to hear about the jealousy issues. We have definitely seen our share of that with DS as well. He seems to be slightly better lately though, a bit more accepting of me spending time taking care of her.
EC is going pretty well, although not as well now as when she was 2 months. But yeah, just trying to have fun with it and stay relaxed. She really loves diaper free time on a playmat, she pees a lot more frequently during that than when she is wearing a diaper. She's also moving around a lot too (rolling and/or scooting herself while on her back) so I think she's busy with figuring that out.
Except for this week with the teething, she finally consolidated her poops to 1-2 a day, we're catching most of them at this point but still do have some misses. I do best with pees when I am wearing or holding her or if she is sitting (in a carseat or bouncy chair). For a few weeks we had pretty much all dry nights but now either she doesn't get upset/vocal enough to wake me up until after she's peed or else I am harder to wake up because I'm getting less sleep these days. If I could get to her quickly enough then she usually would wake up dry.
I wish I could easily take her to the bathroom while shopping but it is too difficult with DS there as well, he would get upset. So what we do when out and about is I have a little potty in the back of the car, potty her before and after we go into the store and in between stores. Don't always make it back in time but she surprises me with how long she'll hold it sometimes (with some major protests in the checkout line sometimes). I use baby legs and sweaters and a potty cozy to help keep her from getting too cold. We use cloth out and about but did have a little stretch of doing disposables leftover from a trip. I think you will settle into a rhythm with him soon enough.