A good way to entice them to eat solid food is to dampen it a bit then put in the the microwave not long enough to make it hot but to make the smell stronger.
I mostly bottle fed my kitten goats milk (on vets advice) till he was able to handle normal solid kitten chow. To much cow milk can do harm. Found him and his mother starving to death, they'd been abandoned and the rest of her litter had already died.
...He got pretty huge. Still tries to squeeze into my shirt pocket where he used to sleep though. He gets this funny disappointed look when he can't get his head in.
Obligatory joke image: