I'd never fly 10 hours with kids that young. Even before masks were required. Have the grandparents fly to you. Pay for their ticket, rental car, anything else they'll need.
ETA- if you do end up flying, if you are polite to the flight attendants and show them you are actually trying to get your kids to keep the masks on then they will be more understanding if you start having problems with your kids being fussy about wearing masks. If you are a dick from the get go about the masks, then be ready for issues with the flight attendants/airline. I fly multiple times a week for work and have seen both instances mentioned above occur several times on several different airlines.