Ask her if she'd ever agree to have her holidays counted against her PTO.

No this isn't normal. That is not guaranteed hours or holiday pay. Most people get at least 2 weeks of PTO AND 6-10 paid holidays. Structured this way, you'd only get 10 days off the entire years, with little to none of it to use as you please. Do not agree to this.

No, it's not normal. It sounds like your MB is being stingy, OP. Paid time off should be separate from paid holidays off. PTO should also not come out of days that the family decides they don't need you to work. That should just be a "free" day.

Originally MB agreed that the list of holidays I submitted would be paid based on guaranteed pay since she would be off those days anyway and obviously not needing me. She then informs me to keep in mind that holiday pay will come out of my accrued PTO. I've never had it structured this way. I said I'd be concerned that then guaranteed pay would not protect me from losing pay when they wouldn't be needing my services and asked for at least half of the proposed holidays to be listed just as paid and not coming out of PTO.

Is this normal? I've never experienced it this way.