If she has mastitis, she most likely needs to be on antibiotics now. Sulfa isn't going to hurt the kits. I use it on kits from birth on up.
Some kits think that formula is poison <rolls eyes> and it takes them a bit longer to get the hang of it. Some never get the hang of it and it is a fight every time. I've found that after a week or so of hand feeding, oftentimes the kits will just come up to the bars of the cage and I can syringe feed them through the wire. They don't have to fight being held and I can feed two at a time that way. Just keep trying. By now they should probably be going over that 1 mL per feeding mark, depending on how often are feeding. They are almost ten days old now so I would expect the amount to be going up a little at a time. By a couple weeks old I can usually get 3 mL into them feeding them every two hours. I let them eat until they stop. It's not always the same, mind you, that's just an average.