Thanks everyone. It is life I guess.
It is not breeding season, and I never expected them to breed, and once I found out I said, 'well, they are doing a good job, it will be nice to have some new chicks, I will get a transition cage ready (for the fledgelings)'. Then the storm, then death, then power outage, then brooder broken, then, then, then.... Im really pulling for her, but one baby is a very hard task.
With finches, 6 seems to be the magic number. Easier to care for a clutch of 6 finches, that are at least 6 days old. Making small quantities of formula and feeding with a dental tool every hour.... and stimulating a feeding response without its companions is, well, daunting. Mistakes get made so easily because the fun gets sucked right out of it. Ill keep everyone updated of course... But it is harder for the little guy to keep her temp and humidity right without the skin of her companions.
She is growing (4 days old), here she is next to a egg for size comparison... I put the eggs back in her little 'nest' as she seems to be getting fussy and trying to move around all the time. It is easier for her if she has some leverage without companions: