Hi Morais,
Query 1&2: To hide or change Header
We currently do not have options to hide or change the SfColorPalatte header but we have taken header TextBlock in code and changed its header.
Qurey3&4: To change swatches or to set default colors
We currently do not have support in windows phone to change swatches without colorpalatte button. We have edited style and hidden the swatches button.
Please find the sample in below link.
Please let us know if you have any queries.
Regards,
Vignesh V