My DD has been slow gaining weight too. AT birth she was 4.2kg and now at ten months she is just over 7.5kg. She has been on solids since 7months (we started a bit late cause of allergy risk). I was told that as long as you can see that they are happy and look healthy, are still getting good amounts of wet and pooy nappies, and are gaining some weight, to not worry too much. Also the weight gain seems to slow down a bit once they become more active eg rolling, crawling etc. DD started rolling at 3 months, crawling at 6months and standing at 9 months, and she never stops moving. Its no wonder she doesn't gain much weight, she is buring it all off quickly.
She also has only just started on 3 meals a day, with snacks every now and again, and bfs about 4 times a day and 3 times over night.
KMH.. I think charlotte is doing fine. Maybe keep trying different foods, Abbey liked pumpkin and sweet potato mixed, until you find something she likes. I would still bf first and then offer solids about an hour or so later, and maybe try at different times of the day.

HTH