So many questions about weaning!

So to start off, my twins are 10.5 months and I would like to wean from breastfeeding around the one year mark. I know many will say I should wean when they ready, and I would but we desperately need more income coming into our household and honestly it's exhausting trying to pump because I can never seem to get more than an ounce out at most. Right now they nurse 4 times a day and eat 3 meals and have at least one snack a day.

My boy takes formula just fine, so I think he'll transition to cow's milk easily, but he also gets constipated easily so I'm wondering if there are better options of types of milk to use?

My girl hates formula, and doesn't care for bottles or sippy cups either. So I feel like she'd much prefer something more similar to breast milk, assuming I can get her to take to a cup.

If you have weaned at 1 year, did you begin introducing whichever new milk you used at an earlier time? Someone suggested giving them an ounce a day around 11.5 months to get them used to the taste. I'd ask their pediatrician but they told me that at 9 months that my babies should be almost completely weaned from breastfeeding, so I don't exactly trust their knowledge on breastfeeding at this point.

Also, my SO and I are going away overnight when they'll be 11.5 months, with my inability to pump much, do you have suggestions for supplementing milk for my girl? I don't want her to be stuck with formula when she truly hates the taste but idk what else to do.