"goats are incredibly difficult to accept another kid"
Not always true. One of mine just lives to mother kids, doesn't matter whose, related or not.
Proved very useful last year when her daughter kidded triplets then was ill with metritis. They ended up sharing,
One kid on her mum, one on grandma and one went between the two.
If your want to milk her anyway save yourself the hassle of weaning later, she'll soon settle.