I've talked to a bunch of dealers, they're all over the place on this. I've heard $100, $500, and no deposit at all. It seems to just really depend on the dealership.
$500 deposit and refundable at the dealer I contacted. Why any dealer would not refund the deposit is crazy as they will have no problem selling the Maverick you ordered at a much higher price.
When the order banks open for 2023 models you must lock in the price with a signed order sheet. They can't add additional fees if it's in writing. You should make sure the dealer initiates a COVP ( customer order verification procedure ).
I would not pay more than MSRP which includes a destination and delivery charge. Of course taxes are required and not included in the MSRP.
Doc fees are a scam and don't fall for some exotic sounding protective coating.