We did this last year and our youngest (10) did fine but the 2 teens really struggled to catch up. Missing what the teacher's lecture or daily instructions are is hard, and you can't get it in a worksheet.
So to answer your questions: be up front w/ the school and tell them your plans, and ask for any work she may need, and plan your vacations when you want. UNTIL you kids are in their teens then you have to fit vacations into their schedule.
You'll have such fun in Dec. The beginning of Dec is already calling to me ( I need to wait 2 more years teens will be grads)