The very fact they are fed seems impressive to me!
I would suggest:
- re fussy dd1, always offer, regardless of refusal
- obv continue giving/extending dd2's repertoire
- once ds on solids, give as much taste variety as possible from weaning, aka family food/BLW.
As you are veggie (as are we) I would suggest things you can pick bits out of for dd1, so she has less of what she will refuse. Eg - veg risotto is v easy (fry a bit of onion if wanted, add arborio rice, then i do lazy risotto and chuck in a ton of stock and stir occasionally rather than prolonged stirring, then add veg and cook till done. Add herbs, parmesan, lemon juice etc.) If the veg is biggish, then dd1 can have half (most) picked out.
Pasta - add cooked veg into those who will and add a little in for dd1 or do as a side salad of cooked veg (my dd at the same age hated veg but would have olives and cucumber as her veg with anything)
Couscous with roasted veg/chickpeas
Yorkshire puds with veg and gravy - at 3 yo dd would eat the YP and the peas, but would sometimes try a 'tree' (broccoli)
Chickpea curry/dahl? would the kids eat that?
Over a week we tend to have as dinners: pasta (pesto, fake carbonara (shrooms, no bacon; veg pasta bake...) , rice (curry, risotto, egg fried) freezer food, lazy (e.g. something on toast), potato (e.g. jacket, roast with veg), stir fry, takeaway/out. Similar, but variations on a theme each week. Curry can be frozen if you have space, but I would use your freezer for chips, ice-cream and peas! For us, we do have freezer food things, but also have eggs, couscous, veg burgers, falafel/hummus/salad, veg hot dogs...
I may only have 1 dc, but as a working parent, I have zero time to cook, so all are under half an hour, start to finish pretty much.
Dd refused all veg till about 6 and is now almost vegan. She prefers her veg raw incidentally, don't know if yours would? I was literally at the end of my tether with her and then all of a sudden it improved!
I wrote an essay...sorry!