I hope I don't come off sounding harsh, but it sounds to me like it's time for mom to take back her role and be the mom here.
Why are they still getting formula rather than regular milk? If there's not a reason they can't drink milk, then I would take the formula away and start them on milk, but ONLY at three mealtimes and two snacks a day. You don't even have to serve milk as the drink for each of those five times, but it will probably be good for beginning the transition. Give them about half a juice sized glass of milk and refill it no more than one time during each meal. It also sound like you might want to start them off with food in front of them, and a glass half filled with water, then after they've eaten some food, offer them the milk. That way they won't be filling up on milk first rather than eating the food.
One thing I keep asking people on here is "do you have them eating at the table with you?" That helps children learn good eating habits (of course it means the adults must be exhibiting good eating habits themselves, but I am assuming you and their father do that).
You say they seem to want to be independent. If you mean by that they are trying to feed themselves... YES! They are more than ready to be independent! Let them! Give them a fork and a spoon and help them learn to use them. Be flexible enough to also let them still use their hands, - even in the 'squishy' food - for a while. I know sometimes adults have a problem seeing kids eat this way at the table, but it's part of the learning process.
Serve the children the same foods you eat, but be sure your diet includes 'child friendly' foods. You may need to cut up, mash or otherwise prepare some of the foods so they can more easily handle them, but you'll be surprised how quickly they learn to do those things for themselves too.
Eliminate any 'between meal' snacking other than a planned morning and afternoon snack that is spaced two hours before or after a meal. For those snacks, a cracker or two and piece of fruit with a small glass of milk or water should be sufficient to hold them until the next meal. You might vary that with crackers and cheese or some other combination. The rule of thumb is one food from each of two food groups, and something to drink along with it.
You may have to endure some complaining from your boys until they get used to you being in charge of their dietary needs, but it will be worth it to you and more importantly to them, in the long run.