PZ I second the idea of feeding isla more mushy foods if it will help full her up. What about porridge, cereal avocado etc. by 11 months ds was feeding himself using a spoon.

I also think you shouldn't worry about your supply. Keep feeding dd. she's getting something and may feed well after your new bub is born. Feeding while pg is tough but there are also advantages.

Just keep ticking along and deal with the main issue at hand which is filling up your little ones tummy. Cows milk, yogurt, puréed etc are great. What about those organic squeeze things from the supermarket.

As n2l said I think it's time to let go of expectations and try to just relax into a new normal.